Looks like this is quite widespread and not really helped by the lack of consistent information on the CMS website.
I have pretty much the same issue with my ex. I pay a significant amount of maintenence and have my son to stay 4 days/3 nights each week. I pay for everything when he is with me and he has a full set of clothes and anything else he needs at my house.
Unfortunately my ex takes the view that my maintenance should cover all costs for our son and i regularly get demands to pay for things which she considers "extra's". Just to reinforce the message that she expects me to pay she tells our son that i will be paying and gets him to ask on her behalf. Up until now I have ended up paying for these on top of the CMS payments whilst at the same time asking her not to involve our son in this. Its our discussion and should never involve him in my view.
Recently however her demands have started to get a little ridiculous so I put my foot down. I am still getting the abusive emails as a result of my refusal two weeks ago to her last demand for more money. I have tried and failed to help her see she is not doing herself or our son any favours by taking such a confrontational approach but it falls on deaf ears.
As a result I have had to take a more hardline approach. She gets the CMS payment. If she asks for a contribution rather than demands full payment to anything she considers extra I will consider it. If she demands or involves our son though I will refuse.
I have done a lot of research on this and honestly believe that openness and good communication is the key to ensuring you both put your childrens needs first and to that end I have suggested many times over the last couple of years that we sit down and negotiate a family agreement. I have no issue with paying more to her provided it benefits our son and my ex is contributing what she can. I do have an issue with her trying to blackmail me into regular unexpected and unagreed costs on top of the already substantial CMS pyments she recieves.
I have written a little flowchart (see attached) on how this works from a legal perspective if you are the Parent with care. I would never show this to her (she would explode) but it is where I expect us to get to eventually.
I think your approach is correct, though it can cause problems initially. The problem with CMS/CSA is that they simply don't have the resources to adjust individual claims and payments to take account of extra payments, which would be the ideal - if PWCs realise that by making extra demands, the maintenance would be cut by the same amount, then there would be no point in them making such demands, but unfortunately, it's just to much administration to consider this.
I would just like to throw in my 10 pence worth on this topic, as for my own sanity I decided to crunch some numbers to see how this maintenance payment works out in reality...
I have a 7 year old with my ex partner and I have him 3 nights a week and she has him 4.
On the assumption the the house costs when he is with us are equal between me, my wife and him these are the numbers I came up with.
Heat, light and water £ 428 again my sons share
Food £3,840
Clothes and footwear £ 600
Total £4,868
Splitting that based on the nights we have him my cost is £1,835 and hers is £3,033, so on that it looks as though it's pretty unfair, however when you then consider the maintenance payments I pay to her my costs increase to £3,335 and hers reduce to £1,533, oh how the tables have turned!
I would be interested to see what peoples thoughts are being able to see how this works in reality and what genius came up with these calculations. As always greed seems to rear its ugly head and the more you give the more they will take
Also this doesn't take into account the fact he has his own room and clothes at our house which we have brought over the years and holidays and treats etc!
Matty, have shared similar thoughts for a long time.
I have 2 kids (11 and 15yo) that i have for 5 nights a fortnight, so she has them 9/fortnight, which means on average in a month she has the kids for 9 days a month more than me.
I'll present my unfairness at the amount in two contrasting ways :
A. For those 9 extra days I have to pay £385/month, or about £43/day for the extra days she has them. If you take the opinion that she should pay the same amount as me for the kids that is then £86 per day that kids cost, This works out at £31,000+ a year costs for 2 children !!
B. Another way of looking at is I pay £385/month and she receives ~£180 child benefit. Meaning that before any of our expenses the kids cost me £385, but she profits by £565. In other words for this 9 days a month extra care that she has she is £950 better off than me. Sp with child benefit considered as well the kids cost well over £100 day !!
AS you said I would be very interested in knowing what genius came up with these figures for child maintenance and how? I see quite a bit written by people commissioned by DWP or other Gov organisations that criticise compliance, but don't see anything written about the mathematical inequality of calculations.