Not all re-routes pay re-route pay.

First is the time limitation. If the re-route gets you back to base more than 4 hours after original sched OR past midnight of same day, whichever later, then you may be entitled to re-route pay (more than 30 hours late if involving an ocean crossing.)

Then, it can't be due to something the company had no control over such as broken airplane, wx delay, airport closure.

The re-route pay (if the re-route met all the above) shows up near the bottom of the time card near GS pay, QCQ pay etc. All the things that are paid extra to the trips up at the top of the time card. It's an extra payment for a portion of the rotation flown, i.e. double pay for that portion.