Beginner: Pod odd question

hi, i just started learning how to play NLHE and im confuse about pot odds. I understand the general idea of how many cards can improve your hand thus giving you a certain amount of "outs". I test the poder odds calculator and here are some results i get.

(http://www.toptexasholdem.com/poker-odds-calculator.php)

Case1:
Player 1: Kh Ah
Player 2: 5s 5c

the calculator shows that player 1 has48% of winning whereas player 2 has 51.6% of winning with a 0.4% missing.

Case2:
Player 1: Kh Ah
Player 2: 7s 7c

the calculator shows that player 1 has47.7% of winning whereas player 2 has 52% of winning with a 0.3% missing.

My question is why does player 2 in case 2 have a higher change of winning? Even he have a bigger pocket pair come play to player one, that doesnt change the number of cards needed for player 1 to win player 2.

Thx

b/c with the 55 the board has more chances to double pair over the 5s rather than the 7s therefore counterfeiting the pocket pair and having the Ace play as a kicker.

the "missing" % are the times when both players will play the board (Like a all flush board or QQQQA)

haha..yea..that make sense..

thx for answering guys