Recipes with both pastry AND strong flour

My wife and I are getting into baking and we’ve ran into several recipes that call for pastry and strong flour. As I understand, the difference between both flours are its gluten/protein content and mixing these both types would yield something akin to AP or anything in between (depending on ratio). Can anyone provide any insight on why they’re mixed other than really wanting to fine-tune gluten content for a dish?

I think you have hit the nail on the head. That is exactly why’d you mix a strong and wheat flour for the balancing of the gluten. However pastry flour is very weak and one would normally mix AP and strong flour for this effect. I think if you were to go down this route i’d keep the ratio of pastry to strong flour lower than AP to strong flour.