Michigan Kitchen Sink Electrical Requirements
Code requires two 20 ampere small appliance branch circuits, which it sounds like you have. There's no requirement that I'm aware of, that the receptacles near the sink have to be separate circuits. Though it could potentially be a local ammendment, so you'd have to chek with your local building department.

NEC also requires all countertop receptacles to be GFCI protected, not just those near the sink.