I'm also curious if it's normal to have a ~1 hour phone interview prior to the POSS? Struck me as odd that several (3-4) people spent that much time talking to me prior to me even taking said test. For all they'd know I'd fail it and they wasted their morning.
(I attempted to edit my original post but the captcha was bugged.)
A phone interview is an hour or so out of someone's day. The POSS exam is half day day event that they have to bring you out for. So it makes more sense to do a basic interview first, especially given travel restrictions right now. After the interview, they can decide if they want to bring you out for the test.
When I tested with Exelon, they brought me out for three days, POSS/BMSC exam, the "supervisor" test (all day role-playing exam), and the interview, but that was six years ago.