If you discount a recurring plan purchase for a client on the check out screen by selecting "Apply Discount", only the payment being made at the time of checkout will have the discount. The next scheduled payment will reflect the current selling price of the plan you sold.
To apply a discount to all payments of a recurring plan, you'll want to use a Promotion & Promo Code.
Create a Promotion to Apply to All Payments
Promotions can be created from the Marketing section of your Walla software.
Go to the Marketing Center tab from the main navigation and select Promo Codes
Select the + Add New Promotion button
Enter your Promotion name (This is the name that will appear on receipts)
Choose whether the promotion discount is a percentage or dollar amount
Select the "Apply by Category = Plans" if this applies to all plans or select "Apply by Item = Plan Name" if this applies to only certain plans.
Select "All Payments" under the Promotion Timeframe
You can also define the number of auto pay payments the promotion will apply to when choosing a promotion timeframe if it's not all payments.