The Slate Political podcast last week (which included guest panelist Megan McArdle, who is no fan of the ACA) went into decent detail on the meaning of the signup statistics we have for ACA right now, including percentages of young signups and the "conversion" of site viewers to paying customers, and my understanding is that you've drastically oversimplified the situation w/r/t "official enrollment figures".

There will be attrition over the next several months, but I don't think it's accurate to say the official figures refer simply to people who "put a plan in their cart".