Yes they are all rated at 26K limiting the MTOW to 74,990kgs. If they had the 27K engines they could lift 79,010kgs I beleive.
What cobblers
Our 800's have 26k engines, and MTOM restricted to 79015 kgs. The MTOW you have there is a company limit to reduce nav charges, that's all, nothing to do with the power of the engines.