On our trailer I noticed the plywood bottom on ours is also 3/8" plywood. In the spring I am just going to replace it with 5/8" plywood to beef it up. Try looking at that option.
2015 Jayco 24FBS Elite Jay Flight
2013 Chevrolet Silverado 2500HD 4X4 6.0L 3.73 Axle
HD Trailering Package with Integrated Brake Controller
Equal-i-zer Hitch 10k/1000