The auditor shall then:

1. (a) Compute and enter in a separate column on the roll the respective sums in dollars and cents, rejecting the fractions of a cent, to be paid as a tax on the property listed. Notwithstanding any contrary provisions elsewhere set forth in the law, all rates applicable to any assessment may be combined into a single figure for purposes of computation and extension of the roll.
2. (b) Place in other columns the respective amounts due in installments.

3. (c) Foot each column, showing the totals.

   Provided, however, that if the assessment roll is a machine-prepared roll the above prescribed computations and entries may be made and entered upon a newly prepared roll which shall incorporate the adjustments authorized by the local board of equalization.