The D&D PHB II description is this:This spell grants you a +2 deflection bonus to AC. In addition, anyone who successfully hits you with an attack takes 1d4 sonic damage.
They are both 1/round levelThis spell grants you a +4 deflection bonus to AC. In addition, anyone who successfully hits you with a melee attack takes 1d8 points of sonic damage and must make a Fortitude saving throw or be knocked 5 feet away from you into an unoccupied space of your choice. If no space of sufficient size is available for it to enter, it instead takes an extra 1d8 points of sonic damage.
The BGTSCC version of +2 deflection doesn't stack (don't know if that is on purpose or just that Deflection AC doesn't stack in general). Can it stack?
If stacking is OP, then what about making the Sonic Shield spell more like the original? Thoughts? Cheers.