Sure, it's most common for people to upgrade and stay in their original base. However, some people occasionally chose to move to another base. They've never forced anybody to move from one base to another that I've ever heard about. Also, you don't necessarily need to be at your upgrade point to swap bases, but there would need to be a need with an open position first.
Also, I've talked to a couple people that had solid qualifications but didn't hear back from anybody after applying, so I directly delivered their resume to get looked at. If you meet the minimums and you really want to give Alpine a try, feel free to PM me and I'll gladly forward your resume directly to one of the Chiefs.