DateTimeDiff returning unexpected values for same-day comparisons in Architect

Trying to filter interactions based on whether they occurred within the last 24 hours. The expression DateTimeDiff(Interaction.StartTime, Now()) seems to ignore the time component and just compares dates. If StartTime is today at 10 AM and Now() is today at 2 PM, it returns 0 days.

I need the hour difference. Is there a way to force DateTimeDiff to return fractional days or hours? GetDayOfWeek isn’t relevant here since I need duration, not the day name. Any syntax tricks for this?