It is the intent of this act that the tax imposed by this act be paid only once. No tax shall be imposed on any instrument which transfers ownership of property or an interest therein if such instrument is given and the transfer made pursuant to a written executory contract upon which the tax has been previously paid. Any instrument which is evidence of indebtedness or of a contract right shall be subject to the tax imposed by this act only to the extent of the new consideration given therefor. An instrument which is given to supplement, reform or correct a prior instrument shall be subject to the tax imposed by this act only to the extent of the new consideration given therefor.

   Any instrument which would be subject to the tax imposed by this act except for the provisions of this section shall state on its face, that the instrument is exempt by reason of the prior payment or partial payment of the tax on another instrument executed on part of the same transaction and the date of payment.