Sounds like Peacemaker, which is where I shoot 1000 yds as well, but not BP of course. But, I've never had to worry about supervised elevation changes, so I'm not sure what's up with that. Their main issues is the backstops at 1000 aren't super high, and they don't want people shooting over them. Also, if you've not shot it yet, when you get to the 1000 yard range, you'll need to verify a 100 yd zero by hitting a clay pigeon on a small hill kind of on the left of the shooting benches. If you can't manage that in a number of attempts (I think 5?), then you're done for the day.
I joined there as well a few years back to get access to 1000 yards, but was disappointed to find out that you can only get to that range on Wednesdays. I understand why, but it should have been documented better as part of the sign up process.