The governing body of any city or town which imposes a license fee or tax, by ordinance or resolution, may pursuant to RCW 82.14A.010 through 82.14A.030 only, fix and impose a license fee or tax on national banks, state banks, trust companies, mutual savings banks, building and loan associations, savings and loan associations, and other financial institutions for the act or privilege of engaging in business: PROVIDED, That the definitions, deductions and exemptions set forth in chapter 82.04 RCW, insofar as they shall be applicable shall be applied to a license fee or tax imposed by any city or town, if such fee or tax is measured by the gross income of the business: PROVIDED, FURTHER, That the rate of such license fee or tax shall not exceed the rate imposed upon other service type business activity: AND PROVIDED FURTHER, That nothing in RCW 82.14A.010 through 82.14A.030 shall extend the regulatory power of any city or town.