So (having only one now) do the Germans get two more reserve points due to the second invasion or are they considered "part and parcel" of the OKW reinforcement.
Just read the rules as they are written.
So, YES you get two Reserve Points even if you got some Reserve points from an Invasion before turn 10.
These two Reserve Points are not related to the ones you were talking about, if they were it would have been explained in the rules.
BTW, look at the next German Event:
[26.2.6] Turn 16, OB Süd Reserves: If still in the German
Garrisons or Destroyed Units Boxes, the OB Süd-labeled
units are dropped onto the table and put into the German
Reserves Box on the side they land on. The German player
also gets two Reserve Points.
Same "Reserve Point" wording, yet "OB Sud" does not release Reserve points otherwise (contrary to the OKW reserves).