Why does Final Destination 5 push the original Flight 180 disaster a year forward?

The original Final Destination movie took place in 1999, as evidenced by the date on the Flight 180 memorial in front of Mt. Abraham High School and possibly Alex Browning's plane ticket as well. This date is reinforced in FD2 and FD3, which occur in 2000 and 2005 respectively. No mention of dates occur in FD4, but the end of FD5 throws everything out of wack, as the date on Sam's plane ticket is pushed ahead to May 13, 2000.

It's unclear why this happens, since it doesn't seem to serve any clear purpose. It seems like it was added in as a last-minute thing as well, if this production footage is any indicator. Some people think it's some sort of alternate timeline shenanigan where everything is pushed a year forward, but idk. What are your thoughts?