I recently experienced the same problem. I switched from 120 grit screen to 120 grit sanding disks from 3M. I get uniform color every time! Only down fall is they only go half as far as a screen but money can't buy a relief of stress.
I'm considering trying 100 grit instead of 120 grit. Only cause the 120 seems to burnish the floor.

Hi

Sandscreen discs are used to remove surface scratches, dulling gloss finishes for re-coating and any floor operation where only the removal of the finish is desired leaving the hardwood flooring beneath unaltered. This system is most desirable in situations where the floor surface being prepared is only slightly worn or re-coating is frequently required (i.e. gymnasium floors).

Avery Carter

Hi Avery---
I think what the first poster is talking about is what 3M calls "easy change" disks, which are one-sided 16" yellow discs, with velcro backing. They're used for final screening before a stain, and it's recommended to put two maroon pads on top on them. They don't leave the same scratches that a screen tends to leave, as they ride the contours of the floor better.

First poster seems to have been replying to another post, and created a new topic.