We were having major aggravation as the same maps on 3 different units were giving us different directions

Anyway this could be the solution for Zumo 550 users.
In settings, Navigation, "Recalculation Mode"..................switch it to "OFF"
Hopefully if you share or plot a route it wont take you where you werent planning or in different directions anymore.
Let me know if this works for you guys.
Cheers