Do note that the Companion Coupons (like from the credit card) are now one-ways instead of round trip (credit card gets 2 one-way instead of one RT coupon). You won't see the option to apply them show up unless you search as one way trips.
I guess this also helps them enforce the rule that you can't use the companion coupon on a Saver fare. Recent attempts would only apply the coupon to value and higher.