I'm a bit late to this party, but if you want the time difference for a sub 24 hour period then simple maths will do:

Code:
$sTime1="23:30:10"
$sTime2="01:40:30"
 
$iTimeDiff=(86400*($sTime1>$sTime2))
	+(3600*Split($sTime2,":")[0]+60*Split($sTime2,":")[1]+Split($sTime2,":")[2])
	-(3600*Split($sTime1,":")[0]+60*Split($sTime1,":")[1]+Split($sTime1,":")[2])
 
"Difference is : "+$iTimeDiff+@CRLF