I did a little digging into the specifics of Section 7 - 10N -12W because I thought there might be some public record information behind the offer you received.  I wondered it I had missed a field order or one or more well permits.   The $18,000/NMA offer seemed to indicate that there should be something but I found nothing.  Out of curiosity, I asked one of the mineral companies that I like and trust to give me an offer for Section 7.  I didn't tell them what your offer was nor who you were.  Their offer was a little higher, $18,250/NMA.  This goes to show you how competitive the market for Haynesville minerals has become.  I would advise waiting for a field order and/or well permits should you care to sell all or a portion of the interest.  Good Luck.