No I did not try the acid, but I did a job not long ago that really wasn't dirty. Used alkaline cleaner, scrubbed with 175, and rinsed. Floor looked great, but after drying still a few dark areas but nothing major. I recommended re-cleaning with RENEW. Floor looked the same. Customer was happy and decided to have a clear seal applied.
My personal rental property had some tile that was stained bad. I cleaned it with stripper, oxy, and tile cleaner. Same process above, but did not do squat. I re-cleaned with RENEW and the floor looked brand new. Old English Wood Floor Cleaner was the culprit that caused the staining.
Another job I cleaned with an acid cleaner and the floor looked awful. I went back a few months later and used the stripper solution and it looked perfect.
Every job is different, and I wish one product would work every time, but that just is not the case.