The ME appears to have been an upgraded last ditch version of the FP4MA sold briefly around 1992/93, just before the merger with MAHO.
This resulted in a low cost 3D machine.
I have found the following picture. Note the absence of handwheels and the totally irregular location of the servo on the right side!
It appears that all ME's had the Contour 3 controls, which was necessary for the 3D capability.
The "E" letter may stand for "einfach" (simple), also indicating a spec'ed down machine.
It is likely that the ME was basically an FP4MA that was modified to have one servo for each axis (MA had only one for the combined z-y axis). This is indicated by the odd location of the servo seen in the picture and the MA style machine base.
An ME is for sale in Germany and provides the following pictures: