You should be perfectly fine since the costumes didn't win an award. It's only frowned upon when you've won a major award before with the same costume, especially if you go from entering it the second time at a smaller convention than the one you previously won at.
2014 Conventions :
Katsucon (Washington, DC) - Megacon (FL) - Colossalcon (OH) - Anime Weekend Atlanta (GA)
Upcoming costumes : Princess Garnet (coronation gown) from FFIX, Edea Lee (various costmes) from Bravely Default, and more!