Full throttle shifts are mostly govoner pressure controlled however, you can try making the bowden cablwe housing shorter.
bowden calbe controls most off full throttle shift points.
modulator controls most shift feel.
There is some crossover and over items that some into play so if adjusting the cable doesn't do it find a reputable tranny guy and have him check it out.
The first signs of wear in a Benz auto are delays into reverse and flared shifts. (not all shifts either)
Project Smoker, '87 603 powered wagon
Hauler, 96 CTD can you say torque?
Toy 73 Cougar xr7 convertible
Acme Automotive Inc.