What is a typical reasonable amount for an executive to charge for commission? Need to have an idea of what to expect.

I think you mean "executrix," not executive. Michigan has adopted the Uniform Probate Code, which allows an executrix to receive a "reasonable" commission, not one unilaterally decided upon by the executrix. The court has the power to determine any dispute over the reasonableness of the fee. Fees for a modest size estate are generally in the range of 5%, although your mileage may vary depending on the nature of the assets, the difficulty in marshaling them and distributing them, and any other factors that apply.