Here is the explaination of both bulbos as per IOSPE -
Internet Orchid Species Photo Encyclopedia
Bulbophyllum trichocephalum - "Found from Thailand to China at altitudes around 800 to 1800 meters as a miniature sized, warm growing epiphyte with tubular shaped, rugose psuedobulbs carrying a single apical, broadly linear, petiolate leaf that has a slender, basal, 1 5/8" [4 cm] long inflorescence with 3 solitary acuminate bracts and carrying a cluster of several to many apical flowers.
This species is similar to B. odoratissimum."
Bulbophyllum odoratissimum - "Found in Assam, Eastern Himalayas, India, Nepal, Bhutan, Sikki, Myanamar,Thailand, Laos, Vietnam and China in evergreen lowland forests and primary montane forests at
elevations of 800 to 2500 meters as a miniature sized, warm to cool growing epiphyte or lithophyte on mossy rocks with subcylindric, spreading pseudobulbs carrying a single,apical, oblong-lanceolate leaf that blooms in the fall and winter on a basal, slender, 3" [7.5 cm] long, many flowered inflorescence that has bracts and a apical cluster of 10 to 20, fragrant flowers held at mid-leaf height. This species is best grown in baskets or pots with an open medium, partial shade, hot temperatures, and regular water and fertilizer."