CMS calculation - seems critically flawed?

Hi all

What do we think about this, is my logic completely insane?

So, let's assume we have 1 child, father earns £30k per year, no other income etc. Father is happy to pay his share of course.

From the gov.uk calculator - https://www.gov.uk/calculate-child-maintenance

Using the above scenario - If the father has less than 1 overnight stay per week, he will pay £299 per month

So, let's think about that £299 per month is father's share - we're told this is the contribution based on father's circumstances for 50% of the child's costs

If the child stays with father overnight more for more than 50% of the time and father pays for the costs when child is with him, then he's already paid his half and there is no CMS to pay, quite correct.

So if we go back to the calculation... if the child stays with father 1 night per week, the monthly amount reduces by £43 to £256 i.e one seventh reduction

if the child stays with father 2 nights per week, the monthly amount reduces by £86 to £213 i.e two sevenths reduction

if the child stays with father 3 nights per week, the monthly amount reduces by £129 to £170 i.e three sevenths reduction

if the child stays with father more than 3 nights per week then there is nothing to pay - as said above..

So, to me, in their calulation for between 1 and 3 nights with father, CMS are saying, the £299 per month is 100% of the child's costs - which of course it is not (or we're told on one hand it is not!!), it should be 50%

So these fractions should be doubled, i.e 1 night reduced by two sevenths, 2 nights reduced by four sevenths, three nights reduced by six sevenths.

The only way the existing setup could possibly be fair is if the mother was to pay father one seventh for one night etc - we all know how that would go!!!!!!!!!

Am I crazy?