At no time do we EVER "lose pay" due to a reroute. When you are awarded a trip as a line holder, whether initial PBS award or any other method, you are always guaranteed the value of the trip as created. Then that is "set aside" and your trip as you fly it becomes a work in progress. Depending on a host of possibilities, the value of your trip might increase or decrease, often several times throughout the course of the trip. Pilots should realize that just because you over blocked an hour on day one of a four day doesn't mean you've automatically made an extra hour. Further changes are always possible.

When the trip as you flew it is complete, then that value is compared to the original value and you get the higher of the two.

Let me put it this way. Let's say you have a five day originally worth 26.15. By day two, due to all sorts of bad weather, you have over blocked a lot and now your rotation shows 28 hours. "We're making time baby!" you say. Then on day three the rest of the trip cancels and you get to go home.

You get 26.15, the original value of the trip. Has the IROPS in this example "cost you?" Absolutely not. In fact in this example you're getting 26.15 for what turned out to be a three day (yes this is an extreme example that likely won't ever happen, but you get the point).

Reroutes can suck at times. I've been there. But they never, ever cost you anything other than hypothetical money. NEVER automatically assume that just because at some point your rotation shows you as "making time" that that is set in stone. Only the original value of your trip is guaranteed. All else is "TBD"