In the pool section, yes, sometimes it is the lower concentration-- ~14.5 Baume, I believe.
Instead, take a walk over to the paint department... It's exactly the same as the pool acid, just labeled for a different purpose-- and it's the full 31 baume concentration, and almost certainly cheaper per gallon than what you are paying at the pool store.
I remember one time, I think it was @ Ace hardware, I discovered it stocked near the cement/concrete... It was being sold as a concrete cleaner.... But it was labeled as 31 Baume Muriatic Acid... If I remember correctly, it might even (rarely) be labeled as hydrochloric acid... But as long as it's 31 Baume it's the right stuff.
Of course, there's no harm in using the lower concentration.... it just costs a bit more, and you have to use more of it-- but the trade off is that there is less off-gassing and odor, so it can be a little more "user friendly"...