The plywood is a vapor retarder. Any (1/8") gaps under the plywood will effective allow moving air to rob you of insulation R-value added on top the sheathing. Still air has R-1 for 1-4". You may grow mold under the sheathing, check annually, with insulation on top.
Clothes taking longer to dry?
Clean the dryer screen in HOT water if using fabric softener sheets.
They leave a residue that impedes air-flow, costing you money.
Clean the ducting in the last six months? 17,000 dryer fires annually!