Subsection (a) shall not apply to a power which enables such person, in the capacity of trustee or cotrustee, merely to apply the income of the trust to the support or maintenance of a person whom the holder of the power is obligated to support or maintain except to the extent that such income is so applied. In cases where the amounts so applied or distributed are paid out of corpus or out of other than income of the taxable year, such amounts shall be considered to be an amount paid or credited within the meaning of paragraph (2) of section
661
(a) and shall be taxed to the holder of the power under section
662.