I've actually had this problem with some of my IRs. I normalize them to -0.3dB but for some reason they are so much louder than other IRs even though all of them should be normalized. Weird stuff. Hmm..
It's not you, it's specific to the FAS platforms. Perhaps for reasons of requiring sufficient headroom underneath clipping the converters at full scale, the normalization standard for these units seems to be roughly 6 dB below what we are used to in the DAW. When creating the files for these two boxes I have to use the normalization in aomDSP. Unfortunately since Lynn isn't around, I'm not sure what the standard is here, but in the past I just converted them with the normal DAW level (-0.3) and the FAS users had the same experience as you: roughly 6 dB too 'loud'.