The 15 lbs Yorkie was changed to it's smaller counter part of today for many reasons. One of them being the health problems that occured in the larger Yorkies, much like the health problems that occur in the extreme of the breed today (tea cups) and that is why BOTH are frowned upon and the standard is what it is today up to seven pounds.
(so the standard was changed, thankfully enough people w/ common sense got together and changed it. That may happen again one day, until then...)
"Then you point out that Ben was 15 pounds
Well if they had set the standard at that and kept it there we wouldn't be breeding 7 pound dogs."