Correct Year Shet Was Born?

There seems to be a consistency problem with the way the years are calculated for the first ten generations. Every chart I have seen has Enosh born in 235, and Shet born in 130. One arrives at 235 by adding 105 to 130. Using the same reasoning, one would arrive at 130 by adding 130 to 0. HOWEVER, Adam was not born in year zero, he was born in year 1. Why wouldn’t this make the birthyear of Shais 131, and move up all the other birthyears by one as well?

According to Jewish chronology, part of a year will be counted as a year, so that if Adam died at the age of 930, it may have been in the 929th year of his life, so that would in fact be year number 930.