I'm saying 'no' here because
A. DHEA' mechanism of action as a masking agent is to increase epitestosterone levels which means it is ONLY good for masking very rudimentary UA samples and only for testosterone, not other analogs. Current testing methods would not be fooled by that.
B. Machida disclosed the supplement containing DHEA and it's banned with the same penalty as any real PED.
The only other option is that Machida and/or his team are really dumb and thought DHEA would get him a shorter suspension.
Machida is a smart guy. He did a really careless thing but, at this point, I'm leaning toward not masking.