Use Partcipant Detail Flexfield Segment to Calculate Earnings Per Interval

For a customer that I'm working with, nearly all incentives paid to Participants are based on a percentage of their base wages.

With that in mind, I created a Segment in the Participant Detail Flexfield (CN_PARTICIPANT_DETAIL_DFF) called "Base Wage" and I'm using it in Plan Component expressions to calculate the comission ammounts to be paid: (Rate Table Rate * Participant.Base Wage)

However, this type of expression only works for "per event" expressions and I must find a way to use it in "per interval" expressions as well.

Does anyone have an idea on how to accomplish this?