Oncids can be real sulky babies when they get repotted.
I understand why you repotted for fear of the 100% moss factor. I think the 50/50 mix is a good one. You're orchid needs to go thru some adjustment time - a month or 2 perhaps, then you should see the bulbs plump back up again. It might even make some new ones soon.
Now, when I repotted my oncids ... I don't water. The moss it squeezed out to dampness and the bark is tossed in dry. I keep the top sprayed for the 1st week, then water very lightly for the new 2 weeks. By the 3rd week its back to normal. This has worked much better for me then the old repot drenching way - I lost too many roots when I forced them to drink and they just wanted to recover from the potting.
I wouldn't worry about you're repotting - just give it a few weeks, it should get better ... easy on the water.