I have a Atwood 77 degree pin box, it is currently mounted as low as it vill go with the bolts in bottom holes then a clear row and bolts in third row. I am considering lowering one more row so bolts ...
Hey Frank...if I am getting a clear picture (without a pic), you will still have the same amount of bolts fastening. The bolts will be closer together, with the pin lower in the side supports.
I think this will work, if you are using a conventional hitch, and don't have a huge pin wt. IMO, this arrangement would remove a bit of strength, especially backing tight, with added side torque.
Try it, watch for any extra movement, or loosening of bolts, or fit between uprights.