Wrong shipping costs + need help with additional calculations

I’m selling a box of items and I know the shipping rates for different regions. When I have Multi-Carrier ShipStation Shipping PRO for WooCommerce calculate the shipping cost, it provides an incorrect result for UPS Ground. Shipping to my own region should come out to be $7.66 but it quotes the customer as $13.11.

Additionally I have these issues:

1. When this box is ordered multiple times, it should calculate it as separate boxes being shipped: if someone orders 3 boxes it should be $7.66 + $7.66 + $7.66 and quote their shipping cost as $22.98 for UPS ground.
2. I can’t seem to remove or override the free shipping option. Is this a store wide setting?
3. and it only displays UPS ground rates (the only enabled shipping service) when customers are logged in, but it obviously needs to do it regardless.