Teajay, you say: "X-150 became the X-150.5 when Pass decided to add the blue meter to the front of the amp, which the X-150 lacked. Otherwise, the amp was exactly the same." The Pass site seems mostly to confirm this, but they do give one measurement which is significantly different from X150 to X150.5: something called "Balanced CMRR" is given as " -85 dB @ 1 kHz" for the X150, but "approx. -70 dB @ 1 kHz" for the X150.5. This suggests that the amps do in fact have some significant internal differences, not just a meter on the front...unless you have heard otherwise from Pass themselves?
