I am going to be installing a 6-port expansion cartridge in slot 1, in to a mics which has a Combo cartridge in place in slot 2. Will this configuration be ok? And, do I have to power down?

Do you have XC software? Yes, you'll have to power down.

Yes it is XC software. My concern is, does it matter which slot the combo card is in?

the combo card needs to be on the right

Thank-you.