Those are too large for your boot model. While 7.5 is the very smallest size that flow suggests for Large, that is at the extreme side of the range and this relies on a bigger than average size 7.5 (there is a huge range in boot dimensions between manufacturers and models).
Well, the Medium bindings were much worse for other reasons. I had 1.5+ inches of overhang on the toe side, and the heel was not even at the edge of the board. I tried to ride on them before exchanging for the large and was way unbalanced.
So it seems that although flow suggests that 7.5 overlaps, their bindings don't really have sizing overlap, but have a sizing gap.
Note that I have another boot, K2 T1 size 8, that is physically too big for the toe strap on the Medium size binding. Even on the last tooth, it's not possible to get a single click. On the Larges, I just did a similar test for heel lift and got similar results. It also had the problem with the awkward green strap being bent way out when the upper portion was on the smallest setting to try and center the pressure. It's possible to pull that out a fair bit so that it all mounts flush with the boot, but the tension when tightened is on the outside.
I wonder if the L/XL overlap (Size 10.5 and 11) has a similar problem.