Here's what the different discount tiers in Wholesale Now mean:
Minimum cart value: applies the discount tier to your selected products when the cart subtotal reaches the value you set.
Minimum line item value: applies the discount tier to your selected products when their line item subtotal (variant price x quantity) reaches the value you set.
Minimum cart quantity: applies the discount tier to your selected products when the quantity of items in the cart reaches the quantity you set.
Minimum line item quantity: applies the discount tier to your selected products when their quantity requested reaches the quantity you set.