More SNR Link Status Confusion

Is the PMP450 platform correctly calculating/displaying this info.  It doesn't make sense to me.   The downlink is running in 8X/8X MIMO-B mode at 89% efficiency with a SNR of 37/32 and the Uplink is running in 8X/4X MIMO-A mode at 99% efficiency with a SNR of 32/37.  Despite the SSR, both Up and Down Links are achieving 256-QAM.  What am I missing?  Both links have the same SNR, albeit on opposite polarities.  

Any ideas?

It looks like a pretty solid link.

Have you run much traffic through it?  Right now, for the radio to up-modulate, traffic must be running through it.  This could indicate that it just hasn't had to dynamically go up in modulation on the uplink because what little traffic has been going through the uplink has been handled quickly (i.e. there's hardly any at all).  

If you are willing to run some traffic through in both directions, and take another look, it may make more sense.  If it still doesn't, post again and I will bring someone in on this that might have more insight.

Thanks Matt.

I thought running the Link Test and flooding the link would cause it to modulate at best case.  Yes, this is a new link with minimal if any traffic at this time.

What, if any, is the recomended duration and packet size of a link test.

The -12dB SSR is why it's running MIMO-A on the uplink. I had a very similar issue recently that Matt and Aaron helped me out with it. H pol Rx on the AP was completely dead. Doesn't appear that's the case with yours. You might want to check for an alignment or LOS issue. Or possible water ingress on one of the coaxes. Had a couple of those recently too.