Hi
I’ve just been working on this myself. And this post had no resolution.
You can use this formula to work out the hours between two date columns:
(((HOUR({End time})*60+MINUTE({End time}))-(HOUR({Start time})*60+MINUTE({Start time})))/60)+((DAY({End time})-DAY({End time}))*24)
It will work across multiple days too, but not across calendar months…