You've very dismissive of his "few extra nights" compared to how strongly you felt your historic extra nights and current admin should mean you benefit.
And I know you say youre asking questions but over 3 AIBU people with various experiences of CB, CMS and coparenting all said "50:50 + 2xCB + £300 dont rock the boat best case youll end up with 50:50 + 1xCB" and now youve pushed so much youre facing 40:60 + £0.
But you dont seem to like the answers we've offered and at one point said why would you listen to strangers online. (Well you arent obliged to but you did ask) You listened to CMS who answered based on misinformation you provided. Who you also now blame.
But you asked us, and our opinions have been a pretty consistent opinion. The array of responses are pretty much the same, they've been proven right time and again. And many have also said, if you dont believe us, get proper legal advice - as the court is involved now. I dont think youre going to get an answer that this will go the way you want from anyone at this point. Best case is this is as bad as it gets. And honestly legal advice for a lawyer you pay is the best way to limit your damage at this point.
And again, it doesnt seem to be about less time with your children, which should mean you need less maintainence, but about the benefits.