Maybe an example will help.
Suppose a servicemember had a loan with a monthly payment of $125. The servicemember went on active duty beginning January 1, 2021. If the SCRA benefit had been applied, the monthly payment would decline top $100. Due to a processing error, SCRA benefits were not applied until August 1, 2021. The servicemember would be owed a refund of $25/month for a 7-month period, for a total of $175. In addition, the payment for the remainder of the covered period would be set at $100 on a go forward basis.
If the loan was paid off before the error was corrected, the entire SCRA benefit would be paid as a refund.
Opinions are strictly my own, and have nothing to do with my employer.