Each designation in a will or other instrument executed either before, on, or after September 9, 1993, in which a bank is designated as fiduciary shall be deemed a designation of the trust company substituted for the bank pursuant to sections 8-230 to 8-233 except when the will or other instrument is executed after such substitution. Any grant in a will or other instrument of any discretionary power shall be deemed conferred upon the trust company deemed designated as the fiduciary pursuant to this section.