The total ammo cutoff doesn't state how much ammo the weapon can hold. Instead, that's for how much signifies "ammo low" for the things that have states attached to "total ammo".

From looking at your picture, you're using h2 master rounds dual as the master. Open that, and scroll down to "Number Elements". Check to make sure it's set with its state attached to total ammo. Other than that, I can't really help.