Wow ! This immediately brings back memories of me reading about a similar result from Je Tsongkhapa who undertook many long retreats. During one intensive four-year tantric retreat, he performed 3,500,000 prostrations and 1,800,000 mandala offerings, underlining the importance of the preliminary practices. There were also marks on the area where Lama Tsongkhapa performed his prostrations. Plus his hands bled from the constant rubbing of the mandala offering retreat. Such inspirations from this great Buddha !
Its very heartwarming to read about Hua Chi too, as his results is attained in this era despite he is 70 years old. Wonderful !