The new 6 speed trans in 6th gear is the same as the 5 speed in 5th gear, no RPM change, it just adds 1 extra gear for closer shifting and such.
I knew someone that replaced his fairly new 2012 motorhome with a 5 speed to a new 2016 6 speed trans motorhome because he hated how the 5 speed shifted in the hills, he lost thousands in trade in and I told him 5 Star Tuning for $425 fix the 5 speed issue, his jaw dropped to the ground he did not know about the 5 Star Tuning.
Also the new 2016 V-10 with 6 speed has 42 less HP..