What it is
An interest-free advance of up to several months of basic pay around a PCS move, paid up front and then collected back out of your paychecks over the following year or so. It shows up first as money in, then as a monthly deduction until repaid.
2026 rate
Repayment is typically spread over 12 months unless you request longer.
What goes wrong
The repayment deduction is the part people forget. If your net pay looks light for months after a PCS, look for the advance pay repayment line before assuming an error.