Commissions - Investment Expenses

Commissions should be entered in the "investment expenses" section, correct? in other works equity broker commissions. the weird thing is that TurboTax seems to ADD it the the tax I owe if I enter it in positive. so I *think* the commission number needs to be entered as negative, correct? there is no feasible way entering commission expense as a positive number should increase your tax obligation.......right? any and all help appreciated