I asked my chief pilot the exact reserve quest this week. I was told that it goes towards your credit for the month and thats it. if you think you will be on reserve and fly a lot then its worth it to keep the trip and maybe end up above guarantee. another benefit is it will raise your raw score. Plus if you end up carrying in a lot of time that sometimes gives you a better chance of a line.

But i traded for a trip this month with a higher time trip next month and it knocked my gurarantee down this month by five hours. so i would look at both months together. in my case it was 65 this month and 70 next month (assume reserve)
when i traded for the trip it was 60 this month and 70next month. so i am trying to trade back for the trip.since there is no way i will be above or even close to gura next month
hope it helps
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