Since 1000 comp dollars (in a year) gets you Black Card, 400 in 5 days should get you free rooms (even on weekends). My guess is that it will take a month before their computer system syncs with your play.
Nope, the computer system updates after every session (I check on my iPhone, my hotel offers/comp dollar balances update right away).
I still had 400 some odd points to go towards a black card but stopped by the host desk on the way out and asked for the update, of course they said yes.
Apparently black chip players aren't good enough for unlimited free rooms at Borgata lol, you probably need to give purple action for that.