I just ran into this problem using Salemaker.
I have attributes that deduct an add on (deduct the pattern etc) that should always be deducted using the discount amount of the inventory item. Yes I have the "Apply Discounts Used by Product Special/Sale:" toggled to Yes just for this attribute.
I recently used Salemaker to put a category of kits On Sale and it won't deduct the attribute properly.

Is there a fix for this yet? I browsed thru the forum and didn't see it. Pardon me if there is and post a link please.
If there isn't, I know I will have to do my flash sales on kits using a different method.

Still love the Zencart and appreciate everyone's hard work!
Thank you,
Mona
www.QuiltsInMontana.com