"What are the odds?" That My Softball Team Makes the Co-Ed Novice League Playoff for 1st Place

The following is a shameless plug for my Clark County Co-Ed Novice softball team in league 480SBM04 - Adult Softball League Co-Ed Novice Mon, "Analyze This":

We're currently 1 game out of first place with the final two games of the season tonight, and if there's a tie for first, those teams involved enter a playoff for first in the league. I applied the MDS Model to our league to gauge the "true" win percentage for each team by runs scored/runs against (adjusted for strength of schedule):

Rank	Home Team	RF	RA	Pyth
1	We Are Here To Drink	200	80	0.842
2	Bunting for Pitches	181	85	0.800
3	Analyze This	170	87	0.773
4	Comic Relief	142	108	0.623
5	Pitch Better Have My Money	101	149	0.329
6	Pitches Get Stitches	72	125	0.267
7	Somerset Stephanie	74	146	0.224
8	Bright Futures Pediatrics	23	183	0.022

Here's the scenario: we're playing "Pitch Better Have My Money" twice, with the top 2 teams in the league, "We Are Here to Drink" and "Bunting for Pitches" also playing twice. If "Bunting for Pitches" can win one or both of those games and we sweep our series, we'll be tied in first place and will head to the playoff. 

So I calculated the odds of this happening, since that scenario is very straight forward. Using our Pyth ratings to project win probabilities, we have an 87.41% chance of beating our opponent in each game (favored by 4.93 runs in each game, with a 76.40% shot to sweep them 2-0). 

There's a 67.18% chance "Bunting for Pitches" beats "We Are Here to Drink" either once (in which case we would face "We Are Here to Drink") or twice (in which case we would face "Bunting for Pitches"). 

Assuming the two series are independent gives 67.18% * 76.40% = 51.33% chance of making the playoff.