Not sure where you are getting your data....here is hodgdons' website. Looks like you are right at max to me.
Also I've had good luck running retumbo in my 300 wby. All my loads have been perfectly "called" or guessed by my quickload program so I think it has the burn rate pretty well "nailed" on retumbo.
I ran you load past quickload and it guesses you will do 3127 fps at 66,000 psi......
I'd say you've hit the max....good job on watching signs!!