Помогите поправить скрипт (выдает не правильный размер диска)

[Setup]
AppName=My Program
AppVerName=My Program v.1.2
DefaultDirName={pf}\My Program
;BitmapResource=Drive:img_small.bmp
[CustomMessages]
rus.DiskName=Имя
rus.DiskFileSystem=Файловая система
rus.DiskTotal=Ёмкость
rus.DiskFree=Свободно
rus.DiskType=Тип

eng.DiskName=Name
eng.DiskFileSystem=File System
eng.DiskTotal=Capacity
eng.DiskFree=Free Space
eng.DiskType=Type

[Code]
#ifdef UNICODE
    #define A "W"
#else
    #define A "A"
#endif

const
#ifndef NeedHDD
  DRIVE_NO_ROOT_DIR = 1;
  DRIVE_REMOVABLE = 2;
  DRIVE_FIXED = 3;
#endif  
  MAX_PATH = 260;
  SHGFI_ICON = $100;
  SHGFI_SMALLICON = $1;
  SHGFI_DISPLAYNAME = $200;
  SHGFI_TYPENAME = $400;

type
  _SHFILEINFO = record
      hIcon: HICON;
      iIcon: Integer;
      dwAttributes: DWORD;
      szDisplayName: array [0..MAX_PATH-1] of Char;
      szTypeName: array [0..79] of Char;
  end;

  _ULARGE_INTEGER = record
      LowPart: DWORD;
      HighPart: DWORD;
  end;

  DriveInfo = record
      DriveName: String;
      DriveFileSystemName: String;
      DriveSize: Extended;
      DriveFreeSize: array [0..1] of Extended;
      DriveType: String;
      DriveIcon: _SHFILEINFO;
  end;


function SHGetFileInfo(pszPath: String; dwFileAttributes: DWORD; var psfi: _SHFILEINFO; cbFileInfo, uFlags: UINT): DWORD; external 'SHGetFileInfo{#A}@shell32.dll stdcall';
function StrFormatByteSize64(qdw: Currency; var pszBuf: Char; cchBuf: UINT): PAnsiChar; external 'StrFormatByteSize64A@shlwapi.dll stdcall';
function GetVolumeInformationLp(lpRootPathName, lpVolumeNameBuffer: String; nVolumeNameSize, lpVolumeSerialNumber: DWORD; var lpMaximumComponentLength, lpFileSystemFlags: DWORD; lpFileSystemNameBuffer: String; nFileSystemNameSize: DWORD): BOOL; external 'GetVolumeInformation{#A}@kernel32.dll stdcall';
function GetDriveTypeLp(lpRootPathName: String): UINT; external 'GetDriveType{#A}@kernel32.dll stdcall';
function GetDiskFreeSpaceEx(lpDirectoryName: String; var lpFreeBytesAvailableToCaller, lpTotalNumberOfBytes, lpTotalNumberOfFreeBytes: _ULARGE_INTEGER): BOOL; external 'GetDiskFreeSpaceEx{#A}@kernel32.dll stdcall';


function BytesToSize(Bytes: Extended): String;
var
    pszBuf: array [0..15] of Char;
begin
    try
        Result := StrFormatByteSize64(Abs(Bytes div 1E4), pszBuf[0], SizeOf(pszBuf));
    except end;
end;

function CharArrayToString(cArray: array of Char): String;
begin
    Result := '';
    while cArray[Length(Result)] <> #0 do Insert(cArray[Length(Result)], Result, Length(Result)+1);
end;

function Size64(QuadPart: _ULARGE_INTEGER): Extended;
begin
    Result := $7FFFFFFF;
    Result := ((QuadPart.HighPart + integer(QuadPart.LowPart < 0))*Result + QuadPart.HighPart + integer(QuadPart.LowPart < 0))*2 + QuadPart.LowPart;
end;


procedure GetDrivesInfo(var DriveArray: array of DriveInfo);
var
    i, e: Integer;
    iIcon: WORD;
    UndefDriveLetter: String;
    DriveType: UINT;
    DrivePath: String;
    VolumeName, FileSystemName: String;
    ComponentLength, SerialNumber, FileSystemFlags: DWORD;
    FreeBytesAvailableToCaller, TotalNumberOfBytes, TotalNumberOfFreeBytes: _ULARGE_INTEGER;
begin
    for i := 67 to 90 do // Loop from C..Z to determine available drives
    begin
        UndefDriveLetter := Chr(i) + ':\';
        DriveType := GetDriveTypeLp(UndefDriveLetter);
        case DriveType of
            DRIVE_REMOVABLE, DRIVE_FIXED: begin
                VolumeName := StringOfChar(#32, MAX_PATH);
                FileSystemName := StringOfChar(#32, MAX_PATH);
                GetVolumeInformationLp(UndefDriveLetter, VolumeName, MAX_PATH, SerialNumber, ComponentLength, FileSystemFlags, FileSystemName, MAX_PATH);
                GetDiskFreeSpaceEx(UndefDriveLetter, FreeBytesAvailableToCaller, TotalNumberOfBytes, TotalNumberOfFreeBytes);
                SetArrayLength(DriveArray, GetArrayLength(DriveArray)+1);
                e := GetArrayLength(DriveArray)-1;
                SHGetFileInfo(UndefDriveLetter, FILE_ATTRIBUTE_DIRECTORY, DriveArray[e].DriveIcon, sizeof(DriveArray[e].DriveIcon), SHGFI_ICON or SHGFI_SMALLICON or SHGFI_TYPENAME or SHGFI_DISPLAYNAME);
                DriveArray[e].DriveName := CharArrayToString(DriveArray[e].DriveIcon.szDisplayName);
                DriveArray[e].DriveFileSystemName := FileSystemName;
                DriveArray[e].DriveSize := Size64(TotalNumberOfBytes);
                DriveArray[e].DriveFreeSize[0] := Size64(TotalNumberOfFreeBytes);
                if DriveArray[e].DriveSize > 0 then DriveArray[e].DriveFreeSize[1] := DriveArray[e].DriveFreeSize[0]*100/DriveArray[e].DriveSize;
                DriveArray[e].DriveType := CharArrayToString(DriveArray[e].DriveIcon.szTypeName);
            end;
            DRIVE_NO_ROOT_DIR: Continue;
        end;
    end;
end;


procedure DriveListViewOnClick(Sender: TObject);
begin
    if Assigned(TListView(Sender).Selected) then
        WizardForm.DirEdit.Text := AddBackSlash(Copy(TListView(Sender).Selected.Caption, Pos('(', TListView(Sender).Selected.Caption)+1, 2)) + Copy(WizardForm.DirEdit.Text, 4, Length(WizardForm.DirEdit.Text));
end;

procedure DriveListViewColumnClick(Sender: TObject; Column: TListColumn);
begin
    TListView(Sender).Tag := Column.Index;
    with TListView(Sender) do
    begin
        if DesignInfo = 0 then DesignInfo := 1 else DesignInfo := -DesignInfo;
        AlphaSort;
    end;
end;

procedure DriveListViewOnCompare(Sender: TObject; Item1, Item2: TListItem; Data: Integer; var Compare: Integer);
begin
    with TListView(Sender) do
    begin
        if Tag = 0 then
            Compare := DesignInfo*CompareText(Item1.Caption, Item2.Caption)
        else
            Compare := DesignInfo*CompareText(Item1.SubItems[Tag-1], Item2.SubItems[Tag-1]);
    end;
end;

procedure GetDiskInfo;
var
    ReadyArray: array of DriveInfo;
    DriveListView: TListView;
    NewColumn: TListColumn;
    ListItem: TListItem;
    ImgList: TImageList;
    i, e: Integer;
    ico: TIcon;
begin
    GetDrivesInfo(ReadyArray);
    e := GetArrayLength(ReadyArray)-1;

    DriveListView := TListView.Create(nil);
    with DriveListView do
    begin
        Parent := WizardForm.SelectDirPage;
        ViewStyle := vsReport;
        ReadOnly := True;

      //SetBounds(WizardForm.DirEdit.Left, WizardForm.DirEdit.Top + ScaleY(40), WizardForm.DirEdit.Width, ScaleY(200));    
        SetBounds(WizardForm.DirEdit.Left, WizardForm.DirEdit.Top + ScaleY(30), WizardForm.DirEdit.Width+85, ScaleY(99));
     
        OnClick := @DriveListViewOnClick;
        OnColumnClick := @DriveListViewColumnClick;
        OnCompare := @DriveListViewOnCompare;

        ImgList := TImageList.Create(DriveListView);
        ImgList.BkColor := Color;
        for i := 0 to e do
        begin
            ico := TIcon.Create;
            ico.Handle := ReadyArray[i].DriveIcon.hIcon;
            ImgList.AddIcon(ico);
            ico.Free;
        end;
        SmallImages := ImgList;

        NewColumn := Columns.Add;
        NewColumn.Caption := ExpandConstant('{cm:DiskName}');
        NewColumn.Width := ScaleX(130);

        NewColumn := Columns.Add;
        NewColumn.Caption := ExpandConstant('{cm:DiskFileSystem}');
        NewColumn.Width := ScaleX(105);

        NewColumn := Columns.Add;
        NewColumn.Caption := ExpandConstant('{cm:DiskTotal}');
        NewColumn.Width := ScaleX(60);

        NewColumn := Columns.Add;
        NewColumn.Caption := ExpandConstant('{cm:DiskFree}');
        NewColumn.Width := ScaleX(90);

        NewColumn := Columns.Add;
        NewColumn.Caption := ExpandConstant('{cm:DiskType}');
        NewColumn.Width := ScaleX(100);

        for i := 0 to e do
        begin
            ListItem := Items.Add;
            with ListItem do
            begin
                Caption := ReadyArray[i].DriveName;
                SubItems.Add(ReadyArray[i].DriveFileSystemName);
                SubItems.Add(BytesToSize(ReadyArray[i].DriveSize));  
                SubItems.Add(Format('%s (%d%%)', [BytesToSize(ReadyArray[i].DriveFreeSize[0]), Round(ReadyArray[i].DriveFreeSize[1])]));
                SubItems.Add(ReadyArray[i].DriveType);
                ImageIndex := i;
            end;
        end;
    end;
end;