1. That guy should not be BMW technician.
2. You really don’t understand why Motul is SM or other XW30 oils (European) are SL, SM and not SN. But you are quick to give an “advice.” API is irrelevant in European engines. Every single European manufacturers approval is more stringent than anything API. API is relevant as much as last year snow. The reason (which was discussed here numerous times and that BMW tech should read it) is that SN oils in XW30 grade have more stringent limits oh phosphorus than SM and SL. Many European oils are packed with additives more so than average ILSAC oil. Some are not (like TPT 0W30 LL01 FE) but some are like Castrol Edge 0W30, Pentosin HP 5W30, BMW TPT 5W30 etc. etc.
However in the end, again, API is IRRELEVANT in European engines.
New API SP has limits on XW40 oils when ut comes to Zinc (800ppm) but do not expect European approved oils to be API SP anytime soon except Pennzoil Platinum Euro 5W40 which jumped on that train even before API SP became a thing.