Substantial extra fee for participation in Honors College?

I've been re-doing the NPC's and tuition calculations as acceptances come in for our D. We were very surprised to see at one school that there's a substantial extra fee for participating in their Honors College, to which she has been accepted. It's an amount that is about 6% of the out-of-state tuition. This seems quite high and it almost seems to penalize the Honors College participants. Have you seen this at any other schools? Is such a fee hidden in some other line item of the NPC? I've seen schools cap the number of participants in their Honors College / Honors Program to keep it administratively manageable. But I don't think we've run across other instances of schools passing that magnitude of program costs along to the parents. Thanks in advance for any clarifying information.