It depends on how the step sequencer is used. If the step sequencer is closed between opening clips from each synth, the step sequencer will pick up the Session Drummer names correctly without a drum map. If the step sequencer is not closed between opening clips from each synth, drum maps will keep the instrument names correct. If using a mix of Addictive Drum and Session Drummer on a regular basis a custom drum map combining both synths might make sequencing easier allowing a single MIDI track to control both synths.