Plant omega-3 ala need to be converted to epa/dha before it can be utilised hence how could we use ala value as omega-3 since it is not 100% convert?

Buy what you need: The key to avoiding all this confusion is to buy what you want or what you need. That means a person should not buy the "precursor" compound or supplement, and then try to figure out how much of it is converted to the active compound that he really is interested in. If one buys only the active compound, he has no confusion at all.