That's pretty poor programming to be honest. I'm not trying to be mean, but it's not an efficient way of training. If you train to get stronger, you'll also be able to do more reps at lower weights. The best way of getting stronger at 225lb on the squat is by being able to squat much more than 225lb. If you get your squat to 315lbx5 you'll probably be able to do 225lbx20 without too much trouble. Doing the same weight to failure until you reach a certain rep limit is hard to quantify, specially with compound lifts.
Do what you want, of course, but I suggest you limit your sets to 5 reps, and strive to add weight to the bar every session, even if it's only 5lb.
I never questioned my way of doing things that way because I always saw progress. Earlier this year I was probably doing 225x3. But I see what you mean. Of course, because I always did 12-10-8 I obviously knew that I could push more weight on everything if I dropped everything down to 5 reps, but I had always thought the 8-12 rep range was ideal.