I just want to tell my experience with Pond Armor after reading about the problems you were having with Sanitred. The Pond Armor is expensive and I didn't get nearly the coverage I thought I would either. I also had a problem with pin holes on my poured concrete basement walls.
But, this was all anticipated. I kinda figured my walls would soak up the product a bit, and I applied a thicker coating than they called for just for my own piece of mind after comparing in my mind the hassle of having to redo this vs paying extra to be sure it was done right the first time. If I tried to get the advertised coverage, I have the feeling I would probably be dealing with some problems like you were.
Its pretty obvious that any company in the market to make money will advertise their product in the best possible light. It doesn't mean they are lying. This Pondarmor is amazing stuff, and I have no doubt that if you had a perfect substrate to apply it to, you could get away with their 60sqft per half gallon as they advertise. Its not in their interest to say that your application can easily take 10 times as much though.
But even with this thick coating..(pondarmor claims a 10mil coating..about a normal layer of paint-- I applied it about a 1/16th inch thick instead) I got lots of pin-holes. I spent a long time going over it fixing these holes. Some places on the wall were so bad with the pin holes that i had to put a chalk grid down and work one square foot at a time to help me get them all.
But this wasn't the products fault but they way I used putty spreaders to apply it. And I knew better than to try filling it until I was certain all holes were filled. IF I did try, the water getting into the concrete behind the Pondarmor would probably have ruined the entire application.
From a customer service angle, Butch at Pondarmor has only ever been promptly helpful and polite.