How does Child maintenance assessment work

My husband is not working so I cannot claim CM via CMS. He has agreed to voluntarily pay into a joint account an equal sum to me, from which we can both draw for a limited few children’s expmeses....with the idea we are paying equally for clothes, music lessons, school transport etc.

If he returns to work in the city earning a substantial wage again I will be better off claiming CMS and getting a higher sum paid to me direct.
If I apply. What happens?
Do they ask for proof of income etc and then tell him what he should be paying and give him a chance to pay me voluntarily?
Do I then get the choice whether I claim through the CMS or is that set in motion automatically?

Ideally I would want voluntary CM with no fees so just wanted to know if the CMS encourage voluntary payment before asking me if I want to claim through them.

Hi

You can work out CM due using this calculator www.gov.uk/calculate-your-child-maintenance

A voluntary agreement to pay is always encouraged but if he refuses to pay the minimum amount, you can apply to the CMS and they can intervene. If CM is collected through them, charges will be applied.

Hadenoughnow