If doing BTO for in-store pickup, can you still do in-store trade-in? Do you pay at ordering or at pickup? I'd like to trade in my 2019 16" MBP. I can't be without my laptop for three weeks or whatever, so I'd do an in-store trade-in. However, if you have to pay at ordering, how does that work? I pay the whole thing, pick up and trade in, and then have $1200 in Apple credit? I don't want to do that...