Has anyone seen any domestic MTM upgrades for 1 certificate or any transatlantic for 2 certs per segment?

I've been told that the pricing is dynamic which usually means that it's tied to the price of the ticket. Has anyone noticed a transition point from 2 to 3 for TATL or from 1 to 2 for domestic. Knowing that would be a proxy for not having the information before you buy the tickets.

Thanks in advance