Hallo Klaus
I certainly agree that it was more difficult for a Sea-plane crew to obtain a victory compared with a land-based fighter pilot like Osterkamp...
....the reason is simple it was "unusual" that you actually met an enemy opponent over Sea, and those you met were probably less aggressive to fight...
However it is possible that the German Sea-plane crews were compensated in some ways, for example "easier" awards...?
It is also "true" in my meaning that the German Marine Force did make a "clear" distinction between "true" Marine pilots and those who flew land-based a/c..
Osterkamps book is usable in my meaning as a counter reference, because most histories in there, do have a historical background, despite that Theo made the stories "a bit" better...

One problem is that he dont have a good historic line, which is easy to follow...
MFJ(later renamed MFJ I) was actually formed already on 1 Febr 1917, when MFFA II was renamed.
At this stage MFFA II only consisted of one-seater pilots, so it was a easy task...!
The "underpart" of MFFA I stationed mostly at Beveren was the same day renamed to "new" MFFA II.
The first victory was scored the same month and two more were scored before late Apr 1917.
However on 30 Apr 1917 MFJ was reported fully operational, which means that it was in full strength, probably 13 pilots and some more ready a/c.
Still in Feb 1917 they fighted with only around 10 pilots and not so good a/c..
The "unlucky" Theo did NOT got the claim on 30 Apr 1917 confirmed, but it is clearly that he was disappointed with this decision for a long part of his life.. :'(
I havent seen the actual proposals for Osterkamp and Sachsenbergs PlM awards, so I dont knew if they were dated after their 15 or 20 victory respectively...?
However I am interested to obtain copies of these proposals, because they can contain valuable information.
The proposal of Christiansen promotion to Kapitänleutnant dR MA is to be found in Freiburg...
:

Gunnar