You are merely speculating about a topic you don't know anything about - without sufficient information at hand.
I received a mantra with omkara from SSRS in 1998. I asked a Sankhya-Yoga scholar (a former TM teacher) about it and he pointed out that it was a traditional polysyllabic maha-mantra and was perfectly acceptable in the view of the Shankaracharya tradition (sampradaya).
