Depends on the “towers”, and the room. Most “decent” towers wouldn’t be bolstered much by a “cheap 10” sub”. Even if the little sub provides more extension, a good tower will usually be pretty sensitive and easy to drive, providing a great deal of dynamic capability. Most 10” subs I know of will run out of steam long before the towers do. Especially if the room is large, and on concrete. Audyssey sets my 12” mains to full, but I’ve settled on 80hz. I’ve run them at 40 and 50 for long stretches, as my mains do a really nice job with midbass. In MY setup, going to 90hz and above makes the room sound tubby. It’s possible that my house curve would need an adjustment to help with that, but 80hz works fine.
Hearing differences in the 40-80 takes time and close listening. Bad setup can make this even harder.