The definative answer on engine flush will appear on both erWin, and also ETKA. erWin will detail the specific procedure, and ETKA will list the specific parts.
As others have said, most stealers are franchises, and don't give a toss about the long-term reliablity of the cars they sell and service. Just look how many official franchised dealers use Quantum oils - they are only meant to use genuine premium brand oils - Quantum are for only independent workshops.
Onto specifics of engine flushing agents. Providing that the engine oil has been changed per recommended intervals (and the correct spec quality oil is used and the filter changed) - then there is absolute no need for engine flushes.
Flushing oils and flushing additives were designed for old skool dino mineral oils, or when oil change interval had exceeded the recommended interval by some margin (usually more than 50% over) and became heavily sludged, or when incorrect oil was used. Another specialist requirement was in two-stroke engines when changing from mineral based oils to vegetable oils . . . . ahhhhhh, those headdy daze of the smell of Castor R racing oils . . . .
So, in summary - DON'T use flushing oils or additives.