Acid malt in Beersmith?

I put in a recipe. Then I go to the mash tab. The software gives me an estimated mash pH (which is almost always right).

I then select acid malt. It tells me how much to add. For instance 11oz.

I then add it into my original recipe. The estimated mash pH does not change. Then the acid malt amount actually increases to 11.5oz.

Does the software not see that the acid malt as acid malt in the recipe and just counting is as the base malt?

I believe that's correct. I use the brewersfriend tool for all my water/acid additions. That has worked perfectly for me.