That's poorly phrased; how about this:
QX will pay for your parking at one base. If you live in base, great, end of story. If you commute from another QX base to your base, (say you live in SEA and are awarded BOI), you get to pick which one they pay for. If you commute from a non-QX location, say SMF to SEA, they'll cover SEA.
There is no such thing as "free" employee parking.
Somebody has to pay, it's just a discounted rate.
(And they don't pay you anything, they pay the airport authority directly.)