I'm not sure what I'm looking for really... maybe some opinions and experience?
I've been seperated from my DD's dad since she was one year old and she is now six. She always spent every other Fri/Sat/Sun night with Dad and a Weds night. Plus two weeks in the summer and some extra nights over Xmas.
It has worked well as far as I am concerned. He pays on the nose CSA guideline maintenance and I pay for everything else. I don't count my house/ bills etc as a cost of my DD's as I would need to pay those anyway, and he has to have those things at his house too for when she stays there. But I pay for everything school related, food in the week, and all her child care costs which are £360 a month on their own.
I have resented paying for all her childcare and all her school dinners as he has his CM pro-rated for the nights she is with him, yet by the time he gets her she's fed and cared for etc, he just has to take her home and to bed - but I have never pushed it as I know legally he doesn't have to pay anything other than his pro-rated 15%. And I suppose I think I'm lucky enough (depressing thought) that he pays anything. Although I don't believe in patting him on the back purely for not being scum 
I have recently made the decison to leave my career so I can be at home for her more, (supported by my DP and some ad hoc consultant work) so childcare costs will be nil in a few months time. This annoyingly coinsided with DD telling me she misses her Dad too much when she doesn't see him Wed-Weds every other week and want's more contact with Dad. I have listened to her and I understand that a whole week every other week is too long not to see dad, particularly when the weekend is so intense with the three nights. So I want to facilitate this and after months and months of asking him on her behalf he has agreed to a Monday night after the weekend she has been with me. She is very happy with this and although I'm a bit gutted as for five years I've been used to things the way they are - I know she comes first.
Anyway - finally I get to my point! I will lose quite a bit of CM because of that Monday night as it takes him in to the 156 nights+ category. I'm put out by that because again, he will be fecthing her fully fed, watered and cared for and merely have to take her home (a drive he does anyway because of work) and look after her for an hour before putting her to bed. He will then give her breakfast in the morning and at school the next day she will eat a school dinner that I have paid for... So, would I be unreasonable to sit down with him and try to arrange something other than what CSA suggests?
To put things in to perspective, on the current arrangement he pays £225 a month and has done for years, on the new arrangement he will pay £169 a month - all for two extra sleeps a month at no cost to him...
If you think it would be reasonable for me to at least broach the subject - how would you suggest I go about this?
I've looked at the private arrangement conversation guides on cmo website but it's hard for me to assess how much she actually costs - for the past five years she has cost way more than twice what he gives me as childcare alone is £360. But I honestly think that £169 probably just about half of her costs what with me being at home so I feel a bit greedy to ask for more - but surely five years counts for something..? and my change in circumstance is for her benefit.
Oh I don't know, I think I just need a sounding board.