Hi,
It seems that there is an easier formula. You can simply define the DateTime column as:
:Date + :Time
Then, set the format to "m/d/y h:m:s".
This may not solve your problem since the data import from Excel may have odd behaviors, but I would give it a try.
If the problem persists, I would check that the data you imported is valid by converting your Time column to Numeric - Best format and check that the same times are coded by the same number of seconds.
Let us know if it works.
Best
TS
Thierry R. Sornasse