The confusion I think comes in what the winning captain is and isn't allowed to pick, and the implications that then puts on the losing captain.
There are 4 options that must be decided by the coin toss: 2 ends and 2 halves to kick off in. The winner can pick either end to play the first half from, or can pick to kick off the first half. They can't explicitly pick to kick off in the second half, that only occurs as a result of picking an end. If they do choose to kick off in the first half the opponent then gets a choice of ends, wheras if they pick an end, the opponent gets no decision to make and must kick off in the first half.
Therefore, I forsee the following problems, all based around the idea that kicking off in the second half might be seen as advantageous by someone:
1. Winning captain says "I'd like to kick off in the second half please". You're then forced to make him pick an end instead, and the angry losing captain feels like his opponent has been given both choices
2. Winning captain picks an end and losing captain wants the 2nd half kick off - again, you must now explain to him that he's obliged to kick off and doesn't get a choice, where the previous time he lost the toss he may then have been asked to make a decision.
It's not the biggest issue in the world, but I do feel like it would have been simpler and felt fairer if both choices were up for grabs, and the toss winner simply gets to select which choice he wants to make.