1. We cannot add more products which are set tier price for customer group to cart when the quantity is more than 1.
2. We cannot remove or update the quantity of product in the shopping cart:
1. If you do not set Minimum order amount, you can add more product to cart as normal.
If you set Minimum order amount, the first mentioned problem will happen, hence, customers cannot add products having tier price with quantity different from 1 to cart, but products having tier price having tier price set for quantity 1 can be added normally.
2. For the second issue, please refer this suggestion:
You are only able to remove or update the number of product if ensuring the condition that Minimum Amount is set. For instance, you set 150 in Minimum Amount, then you can remove/update the quantity of products in cart if the cart total is over or equal to 150 after doing action.
For more information about product, please refer Minimum Order Amount For Customer Group page.
If you need any further assistance, please feel free to contact us.
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