Hi Paphjoint,
Coelogyne taxonomy relies heavily on lip structure, especially keel structure, and to a lesser degree, other morphological characteristics (inflorescence/blooming habit for example). Dudley Clayton, after examining , researching, and comparing descriptions and specimens has determined them to be synonomous (and given the name tomentosa is older, it is given priority). So, while I am not a taxonomist and therefore depend heavily on their research and expertise, I 1) tend to defer to their opinions, and 2) am weary in general of just going by how a flower looks as there can be a great deal of variety within one species (Coel fimbriata, Coel speciosa, Laelia pandurata, just to name a few).
The plant/flower I have matches Clayton's description of Coel tomentosa. Do you have plants labled tomentosa and massangeana? If so it would be interesting and helpful to dig into the descriptions, especially the lip/keel structures to see what you've got. In my opinion, photos and tags aren't the most reliable means of identification. I frequently get mistagged Coelogynes.
Respectfully,
-K