Just how bad is it? We may be overpaying subsidies, underpaying insurance companies, and inflating the number of people who have signed up and paid their premiums.

Without a fully built and operational system, federal officials can’t determine how many of the 8 million Obamacare sign-ups announced last week will have actually paid their premiums. They won’t even know how many enrollment attempts were never completed. That, in turn, could affect the amount of money the government spends on premium subsidies. And once the system finally does all come on-line, the data delays could force a sharp revision in that celebrated 8 million figure.

Obama administration officials originally intended to have the major back-end components of HealthCare.gov working by the website’s launch in October. But the deadline slipped as officials focused their energy on the part of the website that consumers would use to enroll in coverage.

When that front end failed disastrously on Oct. 1, the administration diverted every resource to fix it, further delaying the behind-the-scenes technical functions. The deadline for completing those pieces gave way to January and then to mid-March. Senior officials said early last month that they hoped to have the entire system ready by the summer. Now, even summer appears to be a question mark.

And in what is being termed "the mother of all reconciliations," once the site is completely finished, we'll all get to see how badly the government overpaid or underpaid the insurance companies, and consumers who received subsidies:

The Obama administration posted a document earlier this month indicating that insurers will continue to be paid through an “interim” accounting process — pretty much a spreadsheet and some informed estimates — until at least September. When the permanent system eventually goes live, it could lead to a massive correction that either exposes taxpayers to more costs or puts pressure on insurance companies to raise prices.

“We have the mother of all reconciliations coming,” said insurance industry consultant Robsert Laszewski, using the official term for the correction. “It may be that the administration will not be able to give us a credible enrollment number until then because we really need a reconciliation to accomplish that.”

So Democrats who are dancing around the Maypole may wish to consider that the taxpayers may be tagged with a multi-billion dollar bill once everything is working at the Obamacare website. And the announcement will probably come just in time for the November election.