Since our SPL runs the Troop meetings, I always have time to meet with Scouts before, during or after every meeting. I am also more than happy to go to their home or have them come to mine whenever is mutually convenient. My job is to make sure that Scouts who want to advance, have every opportunity to do so, without adding a single roadblock to the process.
In my opinion, this Scoutmaster is adding hoops to jump through. Is attendance at camping trips an issue Troop-wide? If so, the answer is to figure out why, not force attendance by tying advancement to it.