Sec. 123.
Sales, other than sales of tangible personal property, are in this state if:
(a) The income-producing activity is performed in this state; or
(b) The income-producing activity is performed both in and outside this state and a greater proportion of the income-producing activity is performed in this state than outside this state, based on costs of performance.
History: 1967, Act 281, Eff. Oct. 1, 1967