" rear wheel steering ! "
Perhaps ,
Firstly ,
" Wet " performance is based on use of Reverse Thrust... ( if it allows one u/s, perhaps EFB based calculator )
Also ,Twin Jets with wing underslung engines have a tendency to turn into the crosswind if any residual drift is left on , and High Reverse power is used... There used to be diagrams in the FCTM's that show the fancy Vector diagram of the forces involved.
Solution to the problem... cancel to Reverse Idle and revert to normal instinctive Rudder / Brake use.
Your 25 Knot Crosswind limit for Single Reverse use is possibly to reduce the chances of this forced Asymmetry
causing / increasing the Drifting tendency.... ( depending which side Reverser U/S verses crosswind direction )