What does "First charge at checkout" mean in the billing policy? (Essential Subscriptions app)

On a Pay as you go plan, under Billing policy, a line shows when the customer is charged. For example:

• "First charge at checkout. Then every 2 weeks."
• "First charge at checkout. Then on the 1st of every month." (when Charge customers on is a set day)

It is not a setting, a free trial or a delayed charge. The customer pays at checkout, then on the schedule shown. This line replaced the older "1st charge will be for…" text.

Prepaid plans don't show the line. The blue box at the bottom of Billing policy sums up how they are charged. See Prepaid and Pay as You Go Subscriptions Explained.