I am in the same situation; however, the Superscriber program is defined as follows -
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Become a Starfinder Superscriber!
As a bonus, when you sign up to four physical Starfinder subscriptions you'll qualify as a Starfinder Superscriber and gain access to Paizo Advantage, a discount program that grants you a 15% discount on most products available on paizo.com. More details about Paizo Advantage can be found here.
Additionally, Starfinder Superscribers receive free PDF copies of Starfinder Society Roleplaying Guild scenarios.
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There is nothing saying that you will not receive the bonus of free PDF copies of the Society scenarios until after the first item of each subscription ships. It specifically states that "When you sign up to four physical Starfinder subscriptions you'll qualify as a Starfinder Superscriber." It later states that as a Superscrber you get the free PDFs. So, all guild scenarios since the time of your signing up to the four subscriptions should be available.
I realize this may not be what Paizo originally intended, but it is what the offer states. It has been active on the page for a long time, and should be honored. If the intent is to only have the Superscriber bonus to be after the first item of EACH subscription ships, this should be spelled out in the offer. As of right now, this is not the case with the advertised offer.
