Why didn't this CVS deal work like I thought it would?

I thought I understood how CVS coupons and extrabucks worked, but when I checked out most recently, I didn't get extrabucks when I thought I should. I bought these two items:

Finish Powerball Ultimate Dishwasher Detergent Tabs, 11 ct (Reg price $9.79, on sale for $4.97)
Air Wick® Advanced Scented Oil Plug-In Warmer (Reg price $7.49, on sale for $3.97)

I also had a $3 off airwick coupon, and a $1 off the detergent tabs, so the total should have been around $5 before tax. However, they both also counted towards a "Spend $15 get $3 EB" promotion on lysol, airwick, and finish. Because the total before coupons and sales would be $17.28, I thought I would get the extrabucks, but I didn't get them. Did I just misunderstand how the spend deal worked, or did I do something wrong?