Consent order ?index linking

Not sure if index linking is what I mean! but what is the norm for terming Consent Orders to reflect increased wages or increased value of house?

XH and I married 21 yrs plan Clean Break.
No spousal maintenance. No lump sum. No pensions sharing.
A property adjustment giving him 50% of current equity to be paid when I sell house or youngest child leaves education.

He will pay child maintenance.

I was going to word it that the CM changes when 1st child leaves education (-5%)and 2nd (-5%)and then realised that by the time the third leaves, the 'value' of the money is so different that it's a bit meaningless to be so prescriptive.

Also he is getting 50% of current equity - does this mean he gets a fixed amount or a % of the property value = to what his equity is worth % wise now?

Hope this makes some sort of sense!
Ta muchly!