Non-wheat flours, are they apart of total flour or separate ingredients?

Hey guys, I was looking at KA's New England hot dog bun recipe and saw it calls for potato flour, and it got me thinking. What is the general consensus for writing up formulas that contain non-wheat flour, do you include them in your total flour weight or are they listed as separate ingredients with a percent based off of total flour? I'd like to tweak their recipe but I'm not sure where this should technically fall under. Thanks!