The original 15 year permits ( now 10 year) were intended for farmers and ranchers. Vehicles were limited to half tons. No duallies and no more than 6 lug nuts I have seen on some web sites that trucks carrying campers are not considered RV's and no 10 year permits are allowed. One web site stated that the 3.5 Tonne limits was total weight ( GVW). Another said it was load capacity (GCW). I also noticed that if you apply on line for a permit and your vehicle is not allowed The Banjercito can fine you! Good luck getting this problem clarified. Tequila: Your "Boss" should contact the Secretary of Tourism. The Banjercito is very powerful.
Moisheh