I"m in St. Louis as well. I'm not sure if my problems are specific to L615 or not, but over the last couple of weeks (within the spool period of L615, which I have on both my 622 and 722) I have serious problems tuning in my local HD's via SAT. I haven't noticed any audio dropouts when it is working, but when it isn't working I get no locals signal at all. Sometimes it's specific to a channel like NBC and sometimes it happens to multiple channels like NBC and CBS. I don't recall having any local HD problems before the holidays.
I will double check the software version when I get home and see if i've been spooled L616 yet and if so the state of my tuning problem.
I am in STL as well and I was watching a recorded event off of NBC, and the audio dropouts and freezing picture were worse. L616 has made things worse than they were with L615.