Yes, when the coupon type is Amount in Cart — Fixed Dollar Amount ($) or Percentage of Cart (Subtotal) and Apply Discount to Recurring Subscription Rate is ticked. Limit it with Limit Per Membership Plan and the discount is applied when the subscription is created and carried into that subscription's rate going forward. Note the validation rules: the recurring-rate discount only works with those two coupon types, and it cannot be combined with Exclude Meals from Coupon.