Not sure why a manager would care about that in the slightest. Do well and he'll get a move to a better league anyway.
I don't recall seeing an ability to change games. His substitutions were always like for like. Boring football, all tippy tappy sideways keep posession and keep the pass percentage up crap. Shouldn't have been sacked with one game of the season to go though, that was pìss poor from the board
I don’t have the stats myself but others have shown that he got us a load of points with his subs. It was his biggest strength