In the per SAP replication mode a single copy of the multicast channel is forwarded per SAP. In other words, if a subscriber (in 1:1 mode) or a group of subscribers (in N:1 mode) have multiple hosts and all of them are subscribed to the same multicast group (watching the same channel), then only a single copy of the multicast stream for that group is sent. The destination MAC address is always a multicast MAC (there are no conversion to unicast MAC address).
IGMP/MLD states are maintained per subscriber host and per SAP.