Maxillaria ID help

I acquired this maybe 4 or 5 years ago labeled Max.parkeri. I was quite literally thrilled when I saw that, after babying it and trying everything from hot to cold, high light, low light, dry spell, no dry spell, etc, the robustly healthy now-30 growth plant showed spikes coming - 18 of them in fact. I was deliciously anticipating those flat rounded concolor canary yellow flowers and white lip. This plant takes up a lot of prime real estate in my waaaay overcrowded greenhouse, but it was worth it for those beautiful flowers. Imagine my distress when the first flower opened and it is not in fact parkeri but some other plant whose flowers I find rather ugly.

Any ideas on what I should put on the tag when I put it on my trade/sale list this spring?

The flower is 1.75" (4.4cm) across, the oval, flattened pseudobulbs are about 2.5" (6.4cm) high and the leaves are up to 15" (38.1cm) long. Any help with the ID would be greatly appreciated. There is no chance this is a variant of parkeri - size, shape and color are all wrong, and it doesn't look like the pic of the original plant's flower (from which this is a division). I emailed the vendor from whom I got it today but haven't heard back yet.

Meanwhile, enjoy the mystery!