WHAT IS INCREASE?
INCREASE is what God designed into creation in the arenas of PRODUCE, such as what comes from the fields, orchards, vineyards. A man plants each seed, and each seed produces INCREASE because of God's handiwork, not man's. God Himself furnished the increase by His own hand, therefore man enjoyed an increase that, by himself, could NEVER have been accomplished.
Wages are NOT anywhere in scripture classified as a form of INCREASE.
Simply stated: WAGES are an EXCHANGE of one's labor, time and skills for money, or some other commodity.
If that were not the case, we would see the Law including any form of compensation for labor, time and skills as titheable, but that clearly is not the case.