First off I think doing Startup Weekends is awesome (I believe the author would approve of that descriptor), just focusing on turning a profit during them I do not see as a worthwhile focus(with exceptions of course), and it seemed to be the author's focus.
As per your point of recurring income. No, I am not taking into account recurring income, because the author does not make it clear what the '267 subscriptions sold' constitute.
For instance he says:
And when I say “what Noah did” I mean exactly what Noah did. Beef Jerky Subscription Service. Period. I “iterated” on the idea exactly zero. Just ‘stole it’ and executed like crazy for two days, along with the seven other people on my team.
However Noah http://www.appsumo.com/sumo-jerky/ required a 3 month minimum subscription with that 3 month period paid up front.
Now in the author's post they mention they sold 3 month subscriptions however the $5340 divides by 20 as exactly the number of subscriptions sold.
So did the author count the 3 month subscription as 3 subscriptions?
Did the author count it as 1 and not count $40 of the revenue?
Did the author do something else, there is not enough information for me at least to determine how the recurring income would be handled next month. So while you can estimate it would double, I do not feel safe making that estimate.