Why do all MLB teams' magic numbers are going up to 163 after the playoffs starts every year of October?

If I understand what you're asking:

At the beginning of a season, every team would have a magic number of 163, indicating the total additional wins by leading team and additional losses by trailing team needed to clinch a division for the leading team. However because every team is 0-0, no 1 team has an advantage and therefore is no closer to clinching the division. A plus 1 is needed to avoid a tie in the standings, thus 163 instead of 162.

Ie. the formula is (Games in a Season)162 + 1 − (Wins by leading team)96 − (Losses by trailing team)62 = (Magic Number)5.

For example, here is the April 5, 2009 MLB standings, the first game of the year where only the Atlanta Braves and Philadelphia Phillies played a game against one another before anyone else played a single game:

http://mlb.mlb.com/mlb/standings/index.jsp?ymd=20090405

Under formula with all teams at 0-0:
162 + 1 - 0 - 0 = 163.

Hope this helps.

because u can have a one game play off

They don't. The season is 162 games, not 163.

Bob

Can you elaborate further? I think I know what you're talking about,but you're wording is hard to make sense of.