This scheme has nothing to do with how words are written in Assamese; it rather attempts to represent the colloquial Assamese pronunciation of the words in simple roman scripts. The purpose is to assist those who do not know the Assamese scripts and in future to create a computer system that can combine individual syllables (previously recorded or computer generated) to produce the complete word.
By 'syllable', we meant the sounds you can pronounce at one go WITHOUT altering
the position of your lips, tong or breath. These can not be further divided into more discrete sounds. They must also have enough vowels and consonants so that they can be pronounced independently.
‘XOBDO Team’ has not formally adopted any romanization scheme for the other languages. However, there is a plan to do so in near future. Find some examples here.