Do i need to change RMS to AX?

I'm need advice about my current store. We already have Microsoft Dynamic Retail Management System, but we need to fill this feature that RMS not have, such as:
1. Multiple item price, ex : summer promotion or 1 year contract customer.
2. My Sales person can see our item in tablet.
3. Expired date for can food.
4. Multi store, ex if store A & store B have item X out of stock, then our Main Store order it from vendor, not store A & B.

Thank you