Of course they are assumptions, based on what teams have paid in the past for similar or lesser players.
As I said before teams have to be honest with what they have an ask themselves two questions 1) are our chances better than a coin flip to win one playoff round, two play off rounds, three playoff rounds, four playoff rounds? If you do then yeah, lets go for it. Second question if you decide its a coin flip, then what is your best option for the team long term.
IMO, as I stated before, last year was at best a coin flip for us. In all honesty when you look at our performance this year vs Boston and Tampa, can you honestly say our chances are any better? If you are a GM, you have to be willing to be honest with yourself and say this team is probably not good enough to make it past Tampa /Boston