I think I messed up on the taxes so ended up with $4.61 overage and 26 extra points on my 6th redemption. I had coupons for everything but not enough total left over. The cashier rang everything in but couldn't let me add anything. What she did was total everything up and rang up redemption then coupons. She returned items with the leftover coupons then repurchased the items with the coupons.

Other lesser known tips
-Chose bonus sizes for redemption that are no longer allowed for personalized coupons. Some personalized have very strict weight or quantity counts.
-Ontario is bilingual so you can use both French and English coupons
-Foreign language coupons can be allowed. I've had no problems with P&G foreign language coupons. Sometimes I can score more coupons this way.
-Know what is and isn't taxable- Glucerna drinks are not taxable but the bars are.
-Stacking coupons: Ask if its possible to combine coupon & cheque, manager coupon & manu, attached product coupon & printable.
-Free coupons- SDM takes off the tax now
-Glitched pepsi coupons- I printed off coupons that had a line down the side of the coupon making it invalid. The cashier was able to read the expiry date on the very tiny border and allowed it.