@qbteachmt 

OK, I re-read your posts and now understand that you're saying to use an Addition type Compensation item for the OT instead of an OT item.

But now I'm confused as to how this helps with the OP's request?

The request was:

"The challenge is that any overtime the employee is entitled to falls into the last job that she posts. ... what are others doing to spread overtime across jobs. "

Depending on your settings, doing this will either results in the Addition being pro-rated without control across all of the Jobs used on the earnings table, or not at all. 

But, isn't it the case (real world question, not QB) that the employee's time can be associated with work for particular Jobs?  If so, then wouldn't it be better to use a standard overtime item for the overtime, and use it as many times as needed on the earnings table, for each job where overtime applies?