It sounds like your acid was weaker than advertised, but your TA would have been predicted to rise by perhaps 10 ppm, not 20 ppm, but that's splitting hairs. I'd just see how your pH handles over time at this point. If it tends to rise too quickly still, then you can lower the TA with the procedure again though that can get to be difficult with borates in the water (it takes a lot more acid to lower the pH for the procedure).