ATK+ vs STR+ Materia

[Frein]

STR increases maximum damage range.
ATK keeps damage near maximum.


Example:
Normal damage range 100-130
Increase STR by 20 and damage range will be 120-150
Increase ATK by 20 and damage range will be 140-150

So when making a DD build you would first want to know what is the cap for STR, reach that, then add on as much ATK as you can fit.

Is this actually tested or just a hunch/wild speculation?