With PayWhirl, you can configure what happens after the last installment in your payment plan bills. This is one of the most powerful features of PayWhirl and really gives you control over the plans.
In one setup this can be used to create a plan that automatically renews. Suppose your customer is on an installment plan, with 3 installments of $5 per month. With the "after last installment" feature you can decide to unsubscribe the customer, or you can have them continue on with the subscription.
How is this different then a "no limit" subscription?
There are a few key differences to keep in mind. With this new feature you can choose to subscribe the customer to any of your subscription plans, not just the one they finished. This can be used to chain subscriptions together. Suppose you wanted to create a box subscription with products in a sequence, where each month the customer receives a different box. You can now string together plans for each of these boxes. Although it takes a bit more time to setup initially, this setup can be used to create different orders in Shopify.
Note: This is a fairly advanced feature and requires careful planning to configure.
What does that mean exactly?
One thing to keep in mind, installment plans bill instantly. Say you have a plan with only 1 installment set to bill "on date of sign up". Even if you select every "one month" in the plan setup, it will bill the customer on signup, ending the installment plan that day. If I signed up on Feb 1st, the single installment would bill Feb 1, and then trigger the new feature. If set to unsubscribe they would be unsubscribed Feb 1. If set to subscribe to another plan your customer would instantly be subscribed to that plan and billed that day (assuming of course the second plan is set to bill on date of sign up).
Note: You cannot set a one installment plan to auto renew.