Yap, SPA could be required to operate as a multi-pilot. But for example C525/C525A still not correspond to restriction of Part FCL for hours according to CS-25 (because it is lighter) or CS-23 Commuter category (because it is not propeller driven), right?
But anyway, what about Beech 250/300/350 in their configuration for 9-11 pax? Do you know about other single pilot certified aicraft to unfreeze in multi pilot operations under AOC?