Accurate Child Maintenance Calculation

[Deleted User]

Currently, I have my son 6 days every other week. He spends Wednesdays, Thursdays, Fridays, Saturdays, Sundays, Mondays every other week with me and returns home on Tuesdays after school. 

It works out that my ex has my son 4 nights more a month than I do on a regular month.  I do have my son on the day he goes back to his mother, I give him lunches and transport him to school but he doesn't spend the night with me which I believe the CMS looks at. 

Now I am a firm believer that if each parent has 50/50 access that neither parent should pay the other anything.  When my son is with me I have equal costs and I am not claiming any child benefit which I have no plans to try and obtain should I go to 50/5o I am happy for my ex to still receive that.

I believe I only need to pay maintenance to cover the 4 nights a month she has him which seems fair to me.  I know there there are people will say otherwise I just need to know what and how I can accurately calculate.  If I was to calculate the number of days a year I have with my son including half-term breaks, Easter, Summer holidays and Christmas it would equate to about 179 days which is pretty much 50/50 but I think it would be easier to work out per month based of a regular month.  

Any help would be appreciated.  

Comms69

Whats the actual demand from the ex?