Insulation over plywood

Good afternoon all,
Aluminum cargo trailer with 1" pink foam board in walls. Seams are taped off and covered with 1/2" plywood. Would like to add additional insulation without having to remove that plywood if possible Any harm in adding additional 1" pink foam board over that to increase insulation value? Plan would be to put 1/4" luan over that for finished wall. Wondering if there might be a possible issue of trapping moisture in between the two layers where the 1/2" ply could potentially mold and rot.
I have two roof vents which i leave at least partially open all the time as well as the two side vents that came on trailer for ventilation.
Thanks,
Harry
Aluminum cargo trailer with 1" pink foam board in walls. Seams are taped off and covered with 1/2" plywood. Would like to add additional insulation without having to remove that plywood if possible Any harm in adding additional 1" pink foam board over that to increase insulation value? Plan would be to put 1/4" luan over that for finished wall. Wondering if there might be a possible issue of trapping moisture in between the two layers where the 1/2" ply could potentially mold and rot.
I have two roof vents which i leave at least partially open all the time as well as the two side vents that came on trailer for ventilation.
Thanks,
Harry