Yea, end of inning would be better, and arguably save more time. Starting pitcher gets into trouble one out in, so you bring in a reliever to close out the inning. Why not let that switch happen the next half inning. (assuming he went two batters, two outs) . Otherwise they can face another batter the next inning and then get pulled, introducing another mid inning pitching switch, where today they'd probably pull the guy after those two outs today.