Not an expert but having read almost all the articles written by Deacon on Avweb and having flown many hours between turbo piston engines I am prepared to make the following observations.
1/. Deacon is a VERY knowledgeable and VERY VERY experienced bloke and his contacts within the engine business are more so. The list of experienced CAF (Confederate Air Force) IPs with whom he works/has flown with would make your head spin.
2/. Over 1000 hours between C404, C402 and Aerostar 700p and I never leaned on climb. None of my peers did either and we got good life from the engines. This includes C402As at Talair where they were overhauled 'in house' over and over.
3/. I would be willing to bet Deacon has more knowledge and direct experience of big turbo piston engine operation than any 20 ATSB flunkeys or any 10 posters on this site. Added to that is a keenly enquiring mind when it comes to this sort of thing...not something your average pilot posseses.
Chuck.