No I don't see a discrimination issue (unless you take into account some outliers like FMLA leaves), but do see a processing timing issue. For example, we pay biweekly on every other Friday. To have anything posted to that check, payroll needs the information NO later than the previous Friday to input it prior to payroll running on the Monday of the paycheck week. Each company/payroll is going to have a set schedule that they run payroll on. Some may be more flexible/quicker, but generally they also have to deal with a few days for direct deposit timing/mailing paychecks, transferring data out, etc.
So, in a worst case example, if someone were to request a loan on Tuesday October 25th and payroll was run on Monday October 24th to be paid the 28th (today), they would have to wait until the paycheck dated November 11th to have the deduction come out (assuming the request made it through that transfer process either automatically from online loan request or by paper/entered by hand), then processed on the 11th's payroll and then a day or two (or more) to forward it to the TPA for the TPA to then process the transaction through its system and check to see it was paid prior to processing the loan. I doubt theTPA can see payroll reports and can look at them prior to actual payday (but after payroll processing). We never got information back in the day until the client sent all data via floppy disk/online data transfer/upload (which might mean extra programming on that side for payroll to be able to send that back to them electronically).
Unless the employer is going to assume the deduction will happen correctly and not wait on payroll but just put it through on the next check. But that gets into a small risk of it not getting paid by the participant. Yes $75 is a pretty small amount that should go through, but what happens if it doesn't? What happens if that person is on unpaid leave and never returns and never gets another check? Are you going to deny a loan because someone is on FMLA? You can't unless you deny loans for everyone on every type of leave or you would be discriminating illegally for the employee taking FMLA. Who is going to eat the $75 fee? Or does the loan just not happen? Does the TPA wait to get the $75 before ever doing anything?
It just seems so much simpler to leave out payroll-- I just see so many pitfalls -- they have other choices -- either have the employee pay it directly OR take it out of loan funds. Both of which would cause NO extra processing time and have a lot less pitfalls and a lot less programming/process changing to do.