The starter plate is a very non-intuitive part that partly compensates for the sloping rear armor. The two prongs (very nice!) are supposed to be perfectly horizontal when the plate is mounted on the sloping armor. The same goes for the holes.
Check this out:
http://tiger1.info/EN/StarterAdapter.html
The second, offset hole came with the introduction of the HL230 engine in May '43. The first hole was left for backward compatiblity.
It is generally considered that the introduction of the new turret in July '43 denotes the beginning of the mid era.
Cheers,
/Chris
A little too much is about right...