the 80% "theory" is much more likely to be true, considering the topic of overunity and judging from the one youtube video.
of course he could give extra proof and a do more solid measurement method so that one must reconsider. the same goes for possible replications.
there have been too many (well, 100%?) scams when people would make public their free energy or overunity generators without solid proof, so there is reason to be sceptic until 100% sure.
edit\ there seems to be some new videos which i have not yet seen, maybe i'll have to revise my comment
my measurement was also 15 seconds in contrary to 12 seconds. do it yourself, stop the time when they say "go" and wait until the bottle is full with hho.