Pin Box vs. Truck Bed Wall: How to Avoid Conflict?

Our first pin boxes had square rear corners. Many folks including myself had to cut a 45 off the back end of the box so it would clear the bedsides and tailgate on certain truck/trailers.
Finally the industry went to longer extended pin boxes with the back end cut at a angle which helped in about 99 percent of the time.
However on my previous pin box I had to cut another 1 1/2" off the lower 1/3rd of the pin box/mounting frame for more clearance on the trucks bedsides.