Cover by nature is a subjective call.  "An inch or two" of play is just giving the shooter the benefit of the doubt of the error generated by the SO not being in exactly the same place every time, and not using laser range-finding measuring devices to determine little toe position in the absence of fault lines.  If everyone called it as tight as that bay was called, there would be... many more cover PEs issued thoughout the match than there were.  The only way to remove "opinion" from cover calls is to eliminate the cover rule, or use fault lines.  Till then it is subjective, and the best any SO can do is to give an honest effort to call their bay the same way for everyone.

Nick Y - A24313