Why speculate over how much will be returned and how much...

Why speculate over how much will be returned and how much retained?
The overall amount will have an effect on the share price - that is, the amount the market considers is not already built in - and when the return amount is determined , this will reduce the share price accordingly.
However, just because the directors have put forward a suggested payout formula, that doesn't mean it is set in stone - it will need shareholder approval and why would the shareholders agree to a payout amount that left surplus, unused capital inside the company?
Once any award is made, this becomes a capital management exercise. The Company should only keep what it believes is necessary for its foreseeable operating and development requirements - any other amount should be returned to its rightful owners (the shareholders).