Thank you for this notification and attention to detail, 10.2 kilowatts does indeed equal 13.6784253 HP - which simply must be an oversight, typo or even misleading/false advertisement as such is completely unheard of with a stock 49cc four stroke to the best of my knowledge.
However given the following;
...And they are a forum sponsor??
I must remind folks that motorbicycling.com can in no way be held responsible for the contents of our advertiser's websites or the claims therein. By their sponsorship such vendors are in actuality simply advertising themselves, there is no inferred or overt approval of their methods or products just because they have an advertisement on this site. Such advertisements are primarily to offer you diversity in purchasing options - choices you'll need to make yourself based on reviews and information available on this forum should you wish to heed it.
I would suggest contacting the vendor in question directly to address any complaint, reporting any inappropriate behavior you may see on this forum as well as doing what you've done here - bringing such errors and/or misrepresentation to the attention of our member base.