25 C.F.R. § 20.310
What recurring income must be prorated?
The social services worker will prorate the following recurring income:
(a) Recurring income received by individuals over a 12-month period for less than a full year's employment (for example, income earned by teachers who are not employed for a full year);
(b) Income received by individuals employed on a contractual basis over the term of a contract; and
(c) Intermittent income received quarterly, semiannually, or yearly over the period covered by the income.