Incorrect discount applied on multiple variations

Hi there,
Thanks for creating this simple plugin, and up until now, it has been working fine for us. We appreciate the time and effort put into it, and have donated US$10 for your efforts.

I have noticed a problem with the pricing on variations though… when you add two variations of the same product it will deduct the same discount twice.

See this page for reference:
https://ozhealthcaresupplies.com.au/product/blue-clear-powder-free-vinyl-gloves-100-per-box/

The bulk buys thqt we have added:
Buy 10 for $9 each ($2.00 off!) <br>
Buy 20 for $8.50 each ($2.50 off)<br>
Buy 30 for $8.00 each ($3.00 off)<br>
Buy 40 for $7.50 each ($3.50 off)<br>

For instance:
(10) Blue Powder Free Vinyl Gloves 100 per box TGA Approved – Medium
normally $11, discounted to $9 for bulk buy of 10 units
Total: Normally $110, now $90 (discount of $20)

This is Correct.

But if we then add a different variation from the same product it *doubles the discount* for the two:
(10) Blue Powder Free Vinyl Gloves 100 per box TGA Approved – Medium
(10) Blue Powder Free Vinyl Gloves 100 per box TGA Approved – Large
normally $11, now $8.5p for bulk buy of 20 units
Total: Normally $220, should be $170 (discount of $50)
but instead it applies the total discount twice so the total is now $120 instead.

So your code is picking up that this product now has 20 items ordered and thus a better discount for the customer of %8.50 per item, but it deducts the total discount for EACH of them. If I add a third variation it triples the discount and so on.

Can you look at this please? Or does this product not support variations at all?
If so what else would you receommend?

The page I need help with: [log in to see the link]