Help calculating CM?

[howtodealwithit]

Hi

Could anyone point me in the right direction for calculating how much CM my son's father should be paying? For the third year running I've received a letter stating he should pay nil due to not working - rubbish as he works and he is open about that.

He pays a nominal amount, which may be acceptable, but I want DS to get what he's entitled to. All CM is saved for him and will go towards Uni next year, so I know Im asking too late, but ex has always shirked his responsibilities. I assume he ignores the CM as he knows hes under paying (He's SI, does it also mean he doesnt pay tax?!)

I've tried using the calculator but it doesnt give me the option to include the fact he pays CM for two younger children too?

He see's those children EOW, DS is less frequent due to his age so definitely in the lower end of overnight stays (less than 52 days a year)

Can anyone help?

Thanks

Anyone?

If they are saying that he is not working I’m not sure what you can do? Appeal it with them?

I don't know TBH, I'm trying to work out if it's worth appealing for as it may be what he pays is right - feels wrong considering he has a full time, relatively low pay full time job and he's runs a company on the side too.

I wouldn't mind so much, but he never offers more, never takes DS shopping etc, so it really is very basic what he covers. I just think there's something fishy going on; he's claiming ignorance though..