You have your Michael Alts mixed up. Michael Alt who had a 1773 Indenture of lease from Lord Fairfax in Hampshire VA(now Hardy Co. WV) was the one whose daughter evidentlty married Henry Buzzard. They had a son Michael Buzzard who was named as a grandson of Michael Alt on the lease.
Michael Alt who married Mary Boots(Stieffel)wasn't born until about 1762 and he as far as I have been able to find is not related to the other Michael Alt. Michael Alt who married Mary Boots died in 1825 and Christian Rohrbaugh and his wife Elizabeth are named among the heirs selling his land.