Thanks for posting to the Community.
Were you able to resolve this issue? Please share anything you deem useful here.
Can you share the calculation so I can have a look?
I was able to resolve the issue. The issue was related to the dateTime fields attribute "Adjust Value For Time Zone" being set to True. According to the documentation, a datetime field will convert to the correct time zone in the window but the datebase is actually storing the dateTime as UTC. This works for us since we only operate out of a single time zone but for others it would cause issues.