Volume loss after Ultherapy may be actually caused by thinning of SMAS layer? (Photo)

In Taiwan forums, some people have reported even more serious sagging on their faces after Ultherapy. Some Taiwanese doctors suggest that these people may have undergone Ultherapy too frequently, say once a year, and this makes their SMAS layer get thinner and thinner. When they perform face lifting surgeries to patients who often get this treatment, they can see that their SMAS layer is thinner than normal people. However I can’t find relevant info about this in English.