Approximately one half of the well lateral is in Section 7 and one half in Section 18.  The decimal interest on the unit well for 18 would be reduced by about one half for the new well.

Section 18 is HA RA SUC.  The unit acres are 633.913.  The only unit tract that is close to 75 acres is listed as Nancy H. Green and is shown as 71.715 acres.  If that is correct, use those two numbers in your math along with the royalty fraction and see what you come up with.  Also realize that although the lease may have a legal description of 75 acres and the tract actually surveys as 71.715, the ownership may not be 100% of the tract acreage is the lessor only owns a one third interest.  Leases do not cite the lessor's acreage, it cites the tract acreage.  There can be multiple owners of that 71.715 acre tract.

It is not so much permission to drill one or more wells, it is the "slot" that the lateral must conform to.  I refer to it as a "spacing order".  The well can not be drilled with just that slot approval.  A permit to drill for a horizontal lateral matching that slot must still be applied for and approved.  When a formation is unitized, in this case the Haynesville, all the wells producing from the Haynesville within the boundary of that unit pays royalty or production payments for those unleased to each and every mineral owner.

It sounds like you are referring to a Field Order for alternate unit wells.  Once approved, they are effective indefinitely with no time table required to drill.  In fact, a latter application can supersede a field order.  More often than not, those field orders turn into well permits but trying to figure out when is an art only a few of us have.  Good luck.

Tommy, "filed for permission" doesn't tell me if you are referring to an application for alternate wells (spacing) on the Commissioner's public hearing schedule or Chesapeake (Vine) was issued well permits to drill.