§ 1565. Credit. A buyer shall be allowed a credit against the tax due
on a conveyance of real property to the extent tax was paid by such
buyer on a prior creation of a leasehold of all or a portion of the same
real property or on the granting of an option or contract to purchase
all or a portion of the same real property by such buyer. Such credit
shall be computed by multiplying the tax paid on the creation of the
leasehold or on the granting of the option or contract by a fraction,
the numerator of which is the value of the consideration used to compute
such tax paid which is not yet due to such seller on the date of the
subsequent conveyance (and which such seller will not be entitled to
receive after such date), and the denominator of which is the total
value of the consideration used to compute such tax paid.