Voodoo,
keep in mind that the "allowed operating" time, sometimes referred as TBO, is more complex.. from the DB 605A manual, it is appearant that there were multiple "overhaul" time periods were specified, ie. 10 hour, 25 hour, 50 hour etc., each subsequent being a prescribed time for more and more serious inspecitions. I.e first only replace sparkplugs, while the 200 hour inspection was a "Major overhaul", the engine was taken apart, and was throughly inspected for detoriationgs etc.
The DB 605A manual thus specifies 100 hour TBO for the early DB 605A-0 nullseries, and 200 hour TBO for DB 605 A-1.
I only seen some parts of the DB 605 D manual, often 25 hour TBO time is mentioned, however for the above reasons, I am not sure what kind of overhaul ("Uberholung") this refers to, a minor or major one.
In memoirs of Hungarian 109G-10 pilot Tobak Tibor, it is mentioned the DB 605Ds were needed to be replaced after "30-40 hours". The difference could lay in including /not including the the first hours that were to be run on lower powers (like engines of brand new cars). For ASC, I have no idea, but probably similiar, as the ASB/ASC and DB/DC were similiar in power outputs.
One other thing to be mentioned is that these "low" TBO times were typical for late war, high powered piston engines, and the decrease is largely from the need to check for signs of corrision from use of water injection, not "low production quality".
