Where property is conveyed to a person

(a) in consideration wholly or in part, of a debt due to that person; or

(b) subject to the payment or transfer of money or stock, whether it is or constitutes a charge or incumbrance on the property or not, the debt, money, or stock as the case may be, is to be considered as the whole or part of the consideration in respect of which the conveyance is chargeable with ad valorem duty.