In our system, we use 13-15 1NT. However, in third seat we may open light, so we announce our range as 11-15. Recently an opponent challenged that 1N can only have 4 HCP range, and the director agreed. My question is, a. is it illegal to have a 11-15 range 1N opening? b. is it legal (and ethical) to put our range as 13-15 on convention card, but alert that we might open light in third seat? Thankd for the help in advance.