Maintenence and overtime and pension contributions.

HI this year i have racked up a fair amount of overtime and that will show on next years P60 (2024-2025) for calculation December 2025.

This will be in the region of about 20% over last years P60.  So i will be liable to pay child maintenence based on that when it comes to the recalculation in December 2025.

A few questions,

I know about the 25%, so if i pay an increased amount into my company pension (say 10%) and manage to drop my salary by that magical 25% will i just pay based on my new Gross salary? 

I lost a massive chunk of my pension in the divorce so could do with topping it up anyway.

Or will they make me pay on the basis of the overtime on the previous year? 

I appreciate she will then go for the diversion of income route, i only have 1 job fully PAYE so should be simple for them to see.

Anyone have any experience of how this works in practice

I have and have always paid maintence for my children i just want to limit my outgoings if at all possible.

thanks