Upgraded to Blast!® Pro+ Download speeds up to 300 Mbps, don't get past 120Mbs

I upgraded to the 300Mbs plan last week. Since then we haven't gotten over 100Mbs. Most of the time it is very low compared to where it should be: 50s, 40s, and sometimes in the 30s. I suspect that some switch wasn't flipped somewhere.  Have reset DOCSis 3.1 modem and router.  They had trouble activating my new tv package, maybe related?