[11-C. Power not to recover duty of excise not levied or short-levied as a result of general practice. 152[(1)] Notwithstanding anything contained in this Act, if the Central Government is satisfied

(a) that a practice was, or is, generally prevalent regarding levy of duty of excise (including non-levy thereof) on any excisable goods; and

(b) that such goods were, or are, liable