>This is a known issue. Problem comes from datetime values are stored as 2 integers. Difference would be a whole number only if times are 3hrs and multiples apart. ie: 3:00:00 - 1:00:00 is not a whole number but 4:00:00-1:00:00 or 10:00 - 01:00 is.

Yes, thanks. I knew I ran into this before. But if You use things like
this very seldom, You sometimes don't think of them when "just quickly
writing some lines" and later start to wonder.
So I thought this might be interesting for others too.