Soundboard on my CA ox

[Jmackay66]

After repairing the lifted bridge on my Ox (2009 pre peavey) I notice that when I tune the low E & A strings to standard pitch the soundboard seems to be distorted around the ends and the back of the bridge. Detune the E & A strings and it goes back flat. Upon some internal inspection I notice that there is no bridge plate under the bridge. The braces all look to be attached and in good shape. My question is... Is there supposed to be a bridge plate on these that would help support the top or is the top tough enough to handle the pressure without it?? It stays in tune and sounds good. It has pb12s on it. Any insight on this would be appreciated. Thanks, John