Disaster relief work.

For purposes of the apportionment of any income under this section, the disaster relief work, as defined in s. 323.12 (5) (a) 3., of an out-of-state business, as defined in s. 323.12 (5) (a) 6., shall not increase the amount of income apportioned to this state. For purposes of sub. (9), gross receipts from the sale of property or services as part of performing any disaster relief work are not considered gross receipts from sales received in this state.