Notwithstanding any other provision of this chapter, if the declaration or bylaws so permit, the entire condominium property or some or all of the units included therein may be subject to a single or blanket mortgage constituting a first lien thereon created by recordable instrument by all of the owners of the property or units covered thereby; and any unit included under the lien of such mortgage may be sold or otherwise conveyed or transferred subject thereto. The instrument creating any such mortgage shall provide a method whereby any unit owner may obtain a release of his unit from the lien of such mortgage and a satisfaction and discharge in recordable form upon payment to the holder of the mortgage of a sum equal to the proportionate share attributable to his unit of the then outstanding balance of unpaid principal and accrued interest and any other charges then due and unpaid. Such proportionate share attributable to each unit shall be the proportion in which all unit owners whose units are then subject to the lien of the mortgage own among themselves the common elements and limited common elements as provided in the declaration, and the private elements, or such other reasonable proportion as shall be specifically provided in the mortgage instrument. Such mortgage may contain provisions for converting such mortgage to individual mortgages on the individual units included therein. In the event of such conversion, the mortgage on the individual units shall be entitled to recordation without the payment of the mortgage tax provided for by Section 40-22-2.