Yes it is a Volvo designed but Yamaha built engine and so yes, it will be using a different version of the engine management software to the other models but that should make no difference. At the end of the day, it's a petrol engine reporting a misfire on a couple of cylinders and I'd approach it in exactly the same way as any other petrol engine doing the same.
Firstly, I'd use the Volvo VIDA tool to read the fault codes. Reading these forums has shown that sometimes more generic scan tools provide error codes that don't exactly correspond to the actual Volvo hardware / software. It's good to have the exact fault code and description on hand before starting.
Assuming that it is a misfire, I'd pull the plugs affected and check their state (e.g. burnt electrode, oil contamination etc.). I'd also check that the coil pack (plugged directly into the top of the plug) looks ok (seated ok, no cracks, water or oil) and same with the wiring connector from the loom to the coil packs.
Once that's done, reset the error codes, take it out for a spin and read again. If there is still a misfire, suspect bad plugs then faulty coils packs first, unless additional fault codes from VIDA say otherwise (e.g. I think I'm right in saying that I have read on this forum that a faulty TDC sensor has caused misfire warnings on other owner's vehicles).
You might find this video on plug replacement useful:
https://www.youtube.com/watch?v=cSSjwAKNsHc