Yes, you have put your finger on the major issue - if you put too much pressure too quickly, you can close up the rind before all the whey has drained. This can lead to sour off-taste.
However, once you have reached a point that the rind is closed, I don't think it would necessarily hurt to add more pressure ... it just won't do much of anything, and wastes time.
Also, with a cheese that is salted after pressing, you do need to factor in the continuing drop in pH while in the press. Depending on your milk (how much it buffers) and cultures used, you can leave it too long in the press, letting the pH go too low, and wind up with a cheese that doesn't really match what you are aiming for. My first two or three Goudas were a case in point - they tasted good, mind you, but they were more like a semi-sorta-cheddar than a Gouda, both in taste and in (crumbly) texture. Once I got a pH meter, I discovered that with my store-bought milk, the pH was dropping much faster than the recipes assumed, so I had been leaving them in the press way too long before salting.
