There is no automatic member price on meals, plans or delivery. What a member gets at checkout depends entirely on the coupons you limited to their plan:

• Coupons with Auto Apply Coupon to Cart are added automatically when a member's cart qualifies, and are silently skipped for non-members.
• Coupons with Show as Suggested Coupon appear as clickable buttons in the suggested-coupons list at checkout — but that list is shown to every shopper regardless of membership plan (it isn't even filtered by whether the coupon is active or expired). A non-member who clicks a plan-restricted suggested coupon still gets This coupon is not valid when it's checked.
• Other coupons must be typed into the coupon box.

Everything else at checkout (taxes, delivery fees, tips, payment methods) is unchanged by the membership plan.