Also posted in AIBU for traffic.
The CMS only factor in PAYE which is usually the £12K tax free allowance. This is what CM is based on. However if your ex is self employed, dividends are classed as unearned income until you contact the CMS and apply for an ‘income variation’. Only then will they include dividends in the monthly calculations.
Thought this would be useful for anyone who feels their ex is fiddling the books and you are receiving a low CM amount.