As far as I understand the changes to the CT/TIE rules, they no longer affect ratings but do affect peformance in that they modify the random-factor.
Here's where I start speculating: when a player takes a shot, the ME takes into account the offensive/defensive matchup, adds in a random factor (like a + or - to the result) and compares the result to a predetermined number that indicates success. If you CT, the random factor is boosted in your favour. If you've TIEd, the random factor goes in your opponent's favour. If neither team has CT/TIEd, then enthusiasm is compared and the team with the greater enthusiasm level gets the advantage. The skills of the players haven't changed, but the result of each and every event on the court that uses the random factor is affected.
I could be wrong, but that's how I think the BBs have worked it.