OP, the reason you're getting different answers is because you haven't indicated what your goals are.
Do you want access to pilgrim albergues? You only need one, or enough to hold all the stamps.
Do you want a Compostela? Again, you only need enough to hold all the stamps, including 2 a day for the last hundred km on a recognized Camino. The Compostela does not mention the route you took, nor the distance you covered.
Do you want a distance certificate? Different people have reported different experiences with the Pilgrim's Office on what route and distance is ultimately recorded, but, again, you only need as many credentials as you need to hold the stamps.
Do you want the special certificates for completing the Salvador (Salvadorana), or the Muxiana/ Finisterrana ( not sure of spelling) ? I *suppose * you could use any credential, but I suspect it's easier on the people issuing the Salvadorana if you used the specific one issued in Léon. Remember that you obtain the Salvadorana in Oviedo, the Muxiana in Muxia, etc.
Clarify your goals, and you'll get tailored advice
