>I've been struggling with rounding time to the nearest 15. Any suggestions? I figured I need to convert the minutes to seconds first but can figure out the equation to round to the nearest 15 minutes.

This will return a number rounded to nearest 15... it's up to you to convert that into hours and minutes.

function minutes15(tnMinutes)

lnHours=tnMinutes/60
lnRound=round(lnHours*4,0)/4
RETURN lnround*60