4-ply vs. 5-ply plywood

huangyhg

4-ply vs. 5-ply plywood
hi,
we had a city inspector stop the contractor from sheathing a roof because the plywood was 4 plies instead of 5.  he says that apa requires 19/32" plywood to be a minimum of 5 plies .  i have never heard of this requirement before, and everyone i talked to who works in the state of fl has never heard of this requirement.  is his point ligitmate and if so, how is 5-ply better than 4-ply if the overall thickness is the same? wouldn't more joints (between the plies) mean weaker plywood?  maybe i'm missing something, so i appreciate any input on this.