Yes, if you are bidding reserve, your last layer should contain zero "must off" dates. The company sets certain coverage requirements for every day of the month. Example 50 LC and 52 SC required on Saturday 7 Oct. depending on how many guys above you bid that day off will determine if that day is deemed a coverage day for you. If it is deemed a coverage day and you put that day as "must off" the layer will be dropped, it won't even be considered, so...if you have must off requests in every layer and one of them is on a coverage date, PBS will have to move on to. Layer none, which is, it gives you whatever it wants.

when you bid, you do know the coverage requirements, but you don't know how guys senior to you will bid. It's a safe bet that weekends and holidays will be grabbed as days off first. Once you get to a certain seniority, you are pretty safe from coverage days and can get whatever day off you want (which is awesome).

You can look at the coverage requirements from previous bids on the "PBS report". It's located on the APA web sight under PBS/3XP. You can loo at every person and see when the Line holder, Long Call Reserve, and Short Call reserve coverage dates start to kick in. With this info it's pretty easy to predict how you will sit in the future, with the exception of December. The info is under each persons name (not senior people though) it say LH/LC/SC coverage dates.