Wait...what?
Extensions are always signed at a discount over the projected value of the FA years, or no team would ever sign them.
That's the exchange made for guaranteeing years that were previously not guaranteed. The team assumes that risk in exchange for saving cash on 1-2 future FA seasons.
Market value is probably what I shouldn't have said. But whatever you project those two at I would shave off 1 WAR of their value and sign that extension. I don't think you are going to see any ridiculous savings with either of them. The value will come with having players in their prime and not having the downside of paying them in their decline phase.