Bread Machine Flour vs Bread Flour

=== So my question is, what is the difference between the two flours? ===

Probably not much. The bread machine flour might have a tiny amount of citric acid in it to help the dough retain structure at the warm rising temperature in the bread machine.

Then again, it might not. Having worked for a number of years at a consumer goods company (not food) I now have zero trust in any packaging or marketing material and my slogan is "send me the tech specs!" ;-) Which is very true of flour: unless you ask the manufacturer for the detailed specification sheet you don't know exactly what is in it in terms of wheat type and quality, protein percent, etc.

I would say to buy whichever one is cheaper this week as long as there are no bad additives (e.g. bromates) in either one.

sPh