Has Mocha been in heat yet? It seems to be quite common to have one last growth spurt after the first heat in females.
Both of mine had growth spurts after their first heats. They both came in to heat for the first time at exactly 13 months of age. My oldest yorkie almost doubled her weight after it (not literally, but from 4lbs to around 6lbs). My youngest has not gained that much (as of yet) but has widened her ribcage etc.
