problem calculating time

Thanks muk and bram32.
I tried your code and I get the same errors as in mine.

bram32, do your code works for you? I modified it just to display the errors between Total time and Total sum. I can't explain the results: Total sum is usually more then the wanted time and Total time is more than Total sum! Here is the code (thanks bram32):

	Graphics 800, 600, 0, 2
	SetBuffer BackBuffer()
	
	Dim time#(4)
	
.up	

	For i = 0 To 3
		time#(i) = 0.0
	Next

	
	init = True
	
	Repeat
	
		;calculate time passed
		now# = MilliSecs()
		If init Then prev# = now#: inittime# = now: init = False
		elapsed# = now# - prev#
		prev# = now#
		
		;select quadrant
		mx = MouseX()
		my = MouseY()
		quad = (mx > 400) + (my > 300) * 2
		;set time for selected quadrant
		time(quad) = time(quad) + elapsed
		
		;graphical output
		Cls
		
		;draw grid
		Line 400, 0, 400, 600
		Line 0, 300, 800, 300
		
		;print out times
		For i = 0 To 3
			Text i Mod 2 * 400 + 200, i / 2 * 300 + 150, time#(i) / 1000.0
		Next
				
		;measure total time passed
		tot1# = ((time(0) + time(1) + time(2) + time(3)) / 1000.0)
		tot2# = (MilliSecs() - inittime#) / 1000.0

		;debug output		
		Text 0,  0, "You're in quadrant: " + quad
		Text 0, 20, "Total sum times:      " + tot1#
		Text 0, 40, "Total time millisecs: " + tot2#
		Flip

		;limit to 60 secs			
		If tot2# >= 3.0 Then 
			Err1# = tot2# - 3.0
			Err2# = tot2# - tot1#
			Text 0, 60, "Error1 (Total time - 3 sec.): " + Err1#
			Text 0, 80, "Error2 (Tot time - Tot sum):  " + Err2#
			Flip
			Exit
		EndIf
		
	Until KeyHit(1)
	
	Text 400, 290, "Press space to retry", True, True
	Text 400, 310, "Any other key to exit", True, True
	Flip
	
	Key = WaitKey()
	If Key = 32 Then Goto up
		
	End

The other strange thing is, as muk said, the error/delay is the same for 1 sec, 60 sec or more. I'm not sure to understand your solution muk. I need to flip continuously because of the graphics. How should I wait to get millisecs without flipping?

FiNegirO