My general school of thought on Inside Box vs Outside Box, and don't quote me on this, is that if your opponent brings and outside shooting game vs your Inside Box, you will be vulnerable because the Inside Box is deisnged to take away the inside lanes while your best defender focuses on their best shooter. For example, if your best defender is a PF and their best shooter is a SG, you might be leaving your PF outside too often while trusting your SG can take away the inside lanes in place of your PF.
Reverse for Outside Box. The idea is to take away the outside perimeter while your best defender focuses on their best shooter.
Of course, I could be wrong as this is just the way the defense sounds like it should work.