Why would you care what the fuel manufacturer's recommend. They don't own the engine. For 5-10 seconds the engine might have too much oil in it when it's first started. It circulates through the engine and is exhausted out and is gone until you stop for the day and add more. I haven't looked yet but will; what do the engine manufacturers say about after run oil?

The thinking on this may be regional. Most of the fliers I've hung with seem to do it. I won't argue with people whom don't do it and don't seem to have problems. However, I will continue to do so anyway!