Tiered Pricing for multi units of measure

We sell exam gloves. We sell them by the case and box. We offer a list price, but have customers who have lower tiered pricing because they are large customers we have negotiated a lower prices than a guest.

Example:      
Guest Visitor Pricing:
Box of gloves, price: $10
Case of same glove, price: $100 (10 boxes per case)

Special Customer Pricing:
Box of gloves, price: $8
Case of same glove, price $90 (10 boxes per case)

We set up the product and add attributes for cases and box, but when we get to the tiered pricing section and it only offers the ability to offer different pricing for the base unit of measure - BOX. How can we use this tool or something else within nopCommerce to offer a box price and case price, but then offer tiered pricing for certain customers with lower pricing and have it addressed in a case and box lower price in the tiered pricing section, WITHOUT having to set up a different code in the system for the case and box? Is tiered pricing the answer, or is there another way to address this, or perhaps someone has created a widget that addresses this important issue.

I think you can do some customization like -
You can set tier price adjustments for product attributes.
now it's only one price adjustment.

Thanks Rashad,

So, I believe what you are saying is that it requires customization to be able to do what we need, correct? There is no market widgets that you know of that will accomplish same thing??

Have you considered that rather than attribute for case, that you use a product's "Allowed Quantities" field?

"Enter a comma separated list of quantities you want this product to be restricted to. Instead of a quantity textbox that allows them to enter any quantity, they will receive a dropdown list of the values you enter here."

(probably better for 'inventory' too ;)