Synchronized Subscription question

A synchronized subscription is, as I understand it, a subscription that renews on the same date for all subscribers regardless of when the purchase was made. I have one of these set up to renew monthly.

My question is this: when a purchase of a synchronized subscription is made, it seems to be generating a $0 order at time of purchase, and then the correct value order at time of synchronized renewal (monthly in my case). Is this working as expected? The $0 order seems…odd. There is no set up fee BTW. Is this just to verify the CC entered?