Actually your stat there proves the 'bounce' after changing a coach DOES exist.History shows changing coach doesn’t impact the result with only 7 wins in 18 games since 2000.
Changing a coach doesn’t change means nothing when they have been so poor. They’ve won 9 games in 2 and a half seasons.
For a club to sack a coach mid-season, it's very likely that the team has lost at least the last 5+ games in a row, with some thrashings along the way. Often the players drop their effort and look completely spiritless.
So for those teams to then win almost 50% of their games after the coach is sacked, is a huge spike on their previous run of losses.