Hi here is a sample. I guess the time format here is not a percentage.
-- Is there a specified format in Excel or
-- a handy formula to change a time to a percentage?

If i express the time in numerals, the difference shows as "0" = problem

SDD + CollectionActivity UOMUnitsStartFinishElapsed TimeLost TimeHeldSE = activities per hr309844 AFSearch/Locate/edit/statsTitle112:1012:150:050:0020.0Search/Locate/edit/statsTitle112:1912:240:050:00#REF!Search/Locate/edit/statsTitle112:2512:290:04#REF!Search/Locate/edit/statsTitle112:3112:330:02#REF!Search/Locate/edit/statsTitle112:3412:380:04#REF!Search/Locate/edit/statsTitle112:3912:420:03#REF!

and now with incorrect answers...
SDD + CollectionActivity UOMVolumeStartFinishElapsed TimeLost TimeActivity TimeSE = activities per hr309844 ANFAdd/edit/statsItem112:1512:190:040:0421600.0Add/edit/statsItem112:2012:250:050:0517280.0Add/edit/statsItem112:2912:310:020:0243200.0Add/edit/statsItem112:3212:330:010:0186400.0Add/edit/statsItem112:3812:390:010:0186400.0