He 111P before H. Can someone explain to me how this is so?

[pathology_doc]

I would have thought that the H should have preceded the P?

 

[Grey Havoc]

A previously allocated designation that was reassigned?

 

[Michel Van]

I think that P stand for "Production" Model
Version A to J were step for step development toward the Serial production model P.

But Daimler had problems with production of 601A Engines
So Heinkel had modified the P. again for Jumo-211 Engines, with litte Help of Junkers
Now designated the He 111 H.

 

[Apophenia]

Heinkel was to simultaneously build the He 111P at Rostick-Marienehe (as well as by NDW and Arado), while the He 111H was built at Oranienburg (as well as by Junkers and ATG). Demand on the supply of DB 601 decided the fate of the P-Serie because the He 111P and He 111H were parallel developments. So, 'P' for 'Produktion' doesn't really hang together

Alas, that doesn't address pathology_doc's question. FWIW, there were other designation anomolies. The long-nosed He 111J for the Kriegsmarine, for example, preceded the short-nosed H-Serie. The Zwilling He 111Z designation anomoly is easier to explain