problem calculating time

Edit:
The alternative would be checking the time more often.
Here is my version, it does exactly the same:

	Graphics 800, 600, 0, 2
	SetBuffer BackBuffer()
	
	Dim time#(4)
	
	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
		Next
				
		;measure total time passed
		tot1# = ((time(0) + time(1) + time(2) + time(3)) / 1000)
		tot2# = (MilliSecs() - inittime#) / 1000

		;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# >= 60 Then Exit
	
	Until KeyHit(1)
	
	Text 400, 300, "GAME OVER", True, True
	
	WaitKey()
	
	End

/edit