Are you testing the PCAOM through Full Auto ?
What about blanking then ? Anything you project using any software will have blanking and/or inter-frame blanking. This brings down the duty cycle (output isn't ON all the time) and could explain your loss on the PCAOM...

Best is to wire up your pcaom with a few switches so you can manually turn every line (channel) on or off. This is really the only way to do it.

Also think of the fact that your PCAOM only has a limited aperture. If you have a I-90 with a 3,5 mm beam, you can't pass it through a neos with only a 2,5 mm aperture. The aperture is noted on the label on top of box with the chrystal.
You'll have to move the chrystal up/down and left/right to find the optimum performance (aperture) on the crystal's surface...

I've used NEOS and the only good ones for I70 or I90 are the ones with the 4,5 mm aperture.