I think Flash is right
What Flash says about the Germans buying P-3s to replace their Atlantiques does match what I thought I had read in some authoritative publication.
The DLI guy may have been at the end of a long communications chain running from Germany to BUPERs to a detailer that may have gotten garbled. You say that he finished the German course then the Bureau changed his orders from PEP Germany to the Naval Air Training Command? That seems significant.
BUPERs changing orders happens, like "stuff" happens. That the Germans would seemingly not "purchase" Dutch P-3s and rely on their Atlantiques seems intriguing. What are they thinking?
Their Atlantiques have to be in worse material shape than the Dutch P-3s. Maybe they too will just fade out of the MPA business when their Atlantiques retire from age.
Afterall, the Baltic Sea and North Sea don't seem to be offering any looming and credible threats to Germany.