Yes, your whole plant looks healthy and great. You would never bury the old bulbs-- when they no longer support the plant you would cut them off. But don't do that til they are totally shrivelled and look really terrible.
I lost a whole, beautiful big oncid because I buried the old bulbs too deep. They rotted, and by the time I noticed (the bulbs hold their exterior shape while they rot from the inside out)--By the time I noticed, the rot had spread, and the whole plant was lost in a short time.
The high bulbs (new ones) -- these are the ones the new roots and also new flowers will come from. When you water, be sure the little root nubs on these get wet. If you have any sphag, a single thread of sphag tucked over the little nubs helps keep moisutre in, even when the sphag itself dries out.
You've got a beautiful big healthy plant there. It will do fine. Be careful to not use a pot too big. Go up only one size of pot.
Good luck
