(a) the amount of output tax payable or due upon assessment in respect of such sales or purchases, and

(b) the total amount of output tax claimed for deferment up to the return period preceding the date of such assessment, does not exceed the balance unexpired amount or the balance available amount referred to in sub-rule (3) of rule 165 that the dealer is eligible for deferment, such amount of such tax payable or due referred to in clause (a) shall, notwithstanding that it relates to the period under assessment, be deemed to be related to the return period immediately preceding the date of assessment.

(2) Where, upon assessment of tax made under section 45 or section 46 after the expiry of the available eligible period as referred to in sub-rule (1) in respect of any period falling within such available eligible period, it is found that an additional amount of output tax is payable by such dealer in respect of sales or purchases referred to in section 12 and the aggregate of -

(a) the amount of output tax payable or due upon assessment in respect of such sales or purchases, and

(b) the total amount of output tax claimed for deferment, does not exceed the balance unexpired amount or the balance available amount referred to in sub-rule (3) of rule 165, that the dealer is eligible for deferment, such amount of such tax payable or due referred to in clause (a) shall, notwithstanding that it relates to the period under assessment, be deemed to be related to the latest return period falling within the available eligible period of assessment.

(3) Where a return period or a period of assessment, as the case may be, comprises two parts ,-

(i) one for which a dealer is eligible under clause (a) of sub-section (1) of section 118 or these rules, for deferment of payment of output tax, and

(ii) the other for which he is not so eligible, the tax payable according to return or tax payable or due after assessment shall be calculated separately for each part for payment in the manner referred to hereinbelow, and -

(a) where, after such calculation, an amount of output tax becomes payable, by dealer in respect of the part referred to in clause (ii), he shall pay such amount and furnish his return for such period in accordance with the provisions of section 32;

(b) where an amount of output tax becomes payable after assessment under section 45 or section 46 in respect of the part referred to in clause (ii), the appropriate assessing authority shall specify in the notice to be issued under sub-section (2) of section 45, or clause (b) of sub-section (3) of section 46, such amount and the date of payment thereof;