I think it is highly unlikely, though, that they would produce at the same physical facility an inferior product as an “in-house” store brand label.
The economics of it wouldn't make sense (i.e. idle time to reconfigure the line versus a short run production function / production possibility frontier).
As an auditor, I know with some products (per bills of lading and shipping manifests), that store brands and name brands are indeed manufactured by the same company.
They wouldn't need to reconfigure the line. You simply run a slightly lower grade of input (raw product).
you said....”store brands and name brands are indeed manufactured by the same company.”.....
Well I’ve found store brands tastes are less than name brands in the items I’ve purchased...butter has less flavor, peanut butter tastes like more lard than peanuts..canned peas are flat...and crackers less flavor. So I gave up on store brands becaause the flavor just wasn’t there...so if all they do is change the label why the differences in flavor?