Make sure you didn't buy a 1 way vs a RT price. Your (2) price points are VERY close to exactly 1/2 (or double) the other. FOr a fre to cut in 1/2 1 day, then double the next to within 1-2% seems a bit fishy. It is possible the fare was filed at the rt level, when they wanted it to be at the 1 way, then fixed it as well...is the fare basis code the same?