I think it can be like other payments based off outcomes
So say 800k MO
Both say yea obviously deal goes ahead but player says yes club says know maybe he gets a 100k payment or something like that.
Maybe they forfeits some amount of remaining wage if club says yes and player says no? (Usually options have a date they need to be taken up by)
So I guess maybe it looks something like Brown agrees to 800k over next 3 years. Following 3 years mutual option is 900k as both are likely happy, results are good and player is improving. Club option maybe looks like 1.1m increase, player doesn't really want to stay but will stay for overs. Player option could look like 600k, player wants to stay but has been **** or injured so club gets better value. I guess this is good for a player as it protects their earning potential long term if an injury occurs, whilst giving them options to negotiate within that space.
Or all that could be completely wrong and I am way off the mark.