Our GlobeTrotter sounds like it's similar - it has wood in the back cushions only. Both the seat & the backs have the same amount
of plywood - it's just inside the upholstery for the back and outside on the seat. The seat doesn't need it inside because it lays flat on the plywood base attached to the glides both when they are opened and closed. The backs on the other-hand, use the plywood to support them in the vertical position when the glides are closed and it's made into a sofa AND
to rest on when made into a bed and the glides are open. So it makes sense to have it move with the cushion. Make sense?