Non-resident state tax for Maryland

My wife did some freelance work for a LLC in Maryland (we are resident in Colorado and pay taxes here for last few years).


While preparing the state taxes through TurboTax (Premier edition, CD version), the Maryland state form showed our income higher than what we received as compensation. It seems Maryland consider all kinds of income and it was multiplied with a factor to get to this number. So the adjusted gross income comes out to be slightly bigger. My question is why should Maryland state be considering what we earned as part of our Colorado income (salary, stocks, etc.)?