Entering a non standard student loan deduction in the Usual Amount column ensures that is the default deduction, rather than the amount specified by the tax code.

Entering a value in the Current Period column overwrites the value for the current pay period only.

Entering the value in both places makes the change effective immediately, and ensures the program automatically deducts the amount each pay period.

Note that no communication with the IRD is required for an employee to pay back more student loan than the minimum required.