Two things to be aware of ladies:
First, the UDP -> TCP switch, this is an indicator that your connection to HTC is not great. So don't be suprised if subsequent to the UDP-> TCP switch you see lag, and/or get disco'd. The UDP switch has always been there, its just that HTC has lowered the tolerance a bit in the last patch. If you find you are switching to TCP a lot, get a new ISP.
Second, some real causes of lag. The most COMMON I see is furballs. Think about it, you have 40 planes fighting in close proximity, even with the new prioritised netcode your are receiving 40 x more information that a 1 vs 1.
Now, take a tracert (like pingplotter or visual route) program and run various packet tests, from 128 bytes up to 5k packet sizes (1:40). What you will find is packet loss increases drastically as the packet sizes get bigger.
So next time you start seeing lag, look around, ask yourself are there to many aircraft around? If so go somewhere where the fights a little quieter, see if the lag goes away. If it does, you've just identified your problem, large packets are getting dropped. Theres not much you can do about except move next door to HTC.
Hope this helps some.