Ways to update progress bar - nsis

Question

I want to control progressbar in my nsis installer. Actually I'm using ThreadTimer plugin but I've got big problem with it. ThreadTimer runs function every 10 seconds to update progress bar (increace progress bar value by 1%). The problem is that it crashes stack (as I can see ThreadTimer is using the same stack as NSIS). Crashes stack means that when I want to get value from the stack the value is wrong because of ThreadTimer function action. Any ideas? Maybe there are some other ways to update progress bar?
Those are functions/macros which should update progress bar. Macro StartProgressBarIntervalUpdate starts updating progress bar, macro StopProgressBarIntervalUpdate stops doping it.
Var /GLOBAL ProgressBarPosition
Var /GLOBAL ProgressBarParentWindow
Var /GLOBAL ProgressBarItem
Function InitProgressBar
StrCpy $ProgressBarPosition "0"
FindWindow $ProgressBarParentWindow "#32770" "" $HWNDPARENT
GetDlgItem $ProgressBarItem $ProgressBarParentWindow 1004
FunctionEnd
Function UpdateProgressBarTimer
${If} $ProgressBarPosition >= 30000 ; 100% * 300
StrCpy $ProgressBarPosition "0"
${Endif}
IntOp $ProgressBarPosition $ProgressBarPosition + 300
SendMessage $ProgressBarItem ${PBM_SETPOS} $ProgressBarPosition 0
FunctionEnd
!define StartProgressBarIntervalUpdate "!insertmacro StartProgressBarIntervalUpdate"
!macro StartProgressBarIntervalUpdate
Call InitProgressBar
GetFunctionAddress $UpdateProgressBarTimerFunctionAddress UpdateProgressBarTimer
ThreadTimer::Start /NOUNLOAD 20 -1 $UpdateProgressBarTimerFunctionAddress
Sleep 1000
!macroend
!define StopProgressBarIntervalUpdate "!insertmacro StopProgressBarIntervalUpdate"
!macro StopProgressBarIntervalUpdate
ThreadTimer::Stop $UpdateProgressBarTimerFunctionAddress
Sleep 15000
!macroend
Here are sections which uses progressbar
Var /GLOBAL UpdateProgressBarTimerFunctionAddress
Section BeforeMoveData SEC01
${StartProgressBarIntervalUpdate}
Call core.UnpackExeData
SectionEnd
Section OnMoveData SEC02
Call InstallFiles
Call InstallRegistry
Call InstallShortcuts
${StopProgressBarIntervalUpdate}
...
SectionEnd