Enumerators of each decade census, spelled names their way, many are done phonetically. Also the information on the census was given by a younger member or older member in the household or a neighbor, so you will see variations on the years of birth. I have never hit a census over a 50 year time period that listed exactly the same year repeatedly. Such as my name, you would see Eggbert, or Eggburt. Some got it right, often times they did not.
Also worth noting on the 1900 census of Henry Roy, living with mother and stepfather Morrison, that all in the household is listed born KY, Father born KY, Mother born KY, except for Flora Rea, shows born Missouri, Father Ireland, Mother Kentucky.