Is there a hardware difference between the CPAP-SG750-NGTP and CPAP-SG750-NGTX? According to the datasheet there is not a difference but there seems to be a major price difference. Can a CPAP-SG750-NGTP be upgraded to a CPAP-SG750-NGTX? I was told by a checkpoint rep that they are different hardware so if that is true then would the NGTX have better throughput for traffic with the Sandblast blade turned off when compared to a NGTP? Any assistance would be grateful as I am trying to decide between the 3yr promo for the SG750-NGTP or the 1yr SG750-NGTX.