This is possibly obvious, and I "think" I already know the answer, but let me throw it out for discussion and feedback anyway, just in case I'm wrong.
I decided to test Mirlon Total as a replacement for Abralon and Sia (I like Mirlon Total so far, by the way). I took a new 1500 pad, cut it in half, and used it to sand a Pyramid Curse, 4 sides on a spinner. I then took a 2500 pad and used it to sand an Optimus solid 4 sides on a spinner. As a control ball, I also brought my Hammer Scandal which was lane shined to about 10 games. Off to the lanes we go.
First I threw the control ball, which only moved maybe three or four boards, which is about right for this house and the Scandal since it is so early and so shined. For me, that's about right. Next I took the Optimus sanded at 2500. Effectively... dead straight, maybe 3-4 boards on a good day downhill with a tailwind. I didn't expect that, so I pulled out the Curse freshly sanded 4 sides @ 1500. Dead straight, maybe 4-5 boards. I didn't expect that either.
Totally frustrated at this point and wondering if I was in a parallel universe, I took the other half of the 1500 pad that I brought with me and lightly sanded the Optimus by hand for a few seconds. Total hook city, anything I wanted from anywhere I want. That's interesting. The only difference was by hand vs spinner, and spinner is better, right? I repeated the experiment with the Pyramid Curse, which promptly out hooked the Optimus.
There are only 2 conclusions that could be drawn from this scenario. Number one, never use Mirlon on a spinner. I know it's not made to be used on the spinner, but it shouldn't have caused this issue. Number two, I keep hearing people talk about the difference in pressure applied during sanding. I was really being firm on the spinner, and very light by hand. Personally I think that the answer is I used too much force while sanding.
Thoughts?

I agree, too much pressure when using the spinner.  For me, I've had better results on my spinner using light pressure, just letting the grit do the work.  It's like sharpening knives using stones, where I get wicked sharp edges just letting the stones cut without forcing them with a lot of pressure, which gives bad edges.

Charlest, you're right, I shouldn't really say not for use on a spinner. I think it's closer to say "made for dry sanding by hand", which is not the same thing. Glad to see feedback on the actual cause, which by association also leads to the probability that I'm doing the same thing with Abralon and Sia. I still believe the Mirlon Total has a more uniform and dense scratch pattern than either of the others, and the 360 Mirlon is super for resurfacing. I also got some regular Mirlon off Ebay,which I'll try tonight. It's twice as thick as the Total, but supposedly not quite as aggressive....

Found this excellent article from the archives...

http://www.ballreviews.com/coverstock-preparation/anybody-read-the-btm-article-on-surface-article-inserted-t308227.0.html;msg2529541#msg2529541

Light pressure is certainly the winner, but there is one other observation that occurred to me after reading it...

If two balls are both rated as heavy oil balls OOB, then the ball that is a higher surface OOB will provide close true performance over a longer number of games since the higher surface will experience less total change.

The more I experiment, the more I completely agree. Follow-up question though. I'm experimenting with polish now and finding that  I do not seem to get a high shine using Factory Finish on my spinner. I've tried both light and heavy pressure. I know quarter size on all 4 sides, clean cloth, etc.. but what rules are there re: pressure and time?

Interesting.  I haven't used Factory Finish in quite a while, instead preferring Snake Oil.  Firm pressure until you start generating heat that you can feel will usually generate a gloss finish, at least for me.

Interesting.  I haven't used Factory Finish in quite a while, instead preferring Snake Oil.  Firm pressure until you start generating heat that you can feel will usually generate a gloss finish, at least for me.

Be careful about "generating heat". If you generate too much, you can smooth out all the grit lines you sanding into the ball. If you do, you might as well have sanded it to 4000 and applied any polish.