Just did a little survey for signal strength on the TV.
All 18 channels I pick up are at 100% Signal Strength.
The SNR(db) for them ranges from a low of 23/24 on a couple stations not in question, to a high of 27/28.
The two stations in question show SNR(db) of 24/25 and 100% Signal Strength.
BTW, the engineer I contacted send they'd send someone out to take a look.
So we'll see what comes out of that.
Thanks all for the helpful advice etc...