(1) The concept of taxability in another state is based upon the premise that every state in which the taxpayer is engaged in business activity may impose an income tax even though every state does not do so.   In states which do not, other types of taxes may be imposed as a substitute for an income tax.   Therefore, only those taxes enumerated in 15-31-303, MCA, which may be considered as basically revenue-raising, rather than regulatory, measures shall be considered in determining whether the taxpayer is "subject to" one of the taxes specified in 15-31-303, MCA, in another state.