Blue-Collar;
You stated: " I thought the number itself indicated acid or base"
Yes, the number indicates if it is acid, or, alkaline.
Regarding the PH strength, which IMHO has to be important: As an example, This is why there are average liquid Drain Cleaners, better, and best. Another example I used to demonstrate years back was to use Ammonia as an example. A bottle of Ammonia measured a certain PH.
I took an empty bottle and poured half of that Ammonia into that bottle along with half water. This measures the same PH. Then, I poured 1/4 into an empty bottle and that measured the same PH to.
Which one was stronger? Obviously, the full strength bottle!
Hope this helps.