I just found out that you can still charge meter by hitting your opponent after winning the round. If you have them up against a wall, you can easily do 10+ hit combos and charge plenty of meter for the next round.
I actually encountered a glitch by doing that. I managed to stall the round win animation until the clock reached zero, and then the music abruptly cut out. The sound effects still played, but there wasn't any music until the victory jingle.
