I looked at the quotes and I think they could say the kings served the other
king 12 years, then they rebelled 13 years, and in the fourteenth year (of
their rebelling), the king came to attack them. It does not literally say "in
the 13th year " they rebelled. I am too lazy to look if all quotes that say
in a certain year something happened have the word "in" actually in the
quote. I am sure you or one of the intellectual giants of B-Hebrew would know
the answer to that.