In a Rose Garden speech last month, President Obama defended his health care law, and offered some anecdotes about people it would help. One of those people was Jessica Sanford, who'd written to President Obama describing her health insurance predicament. President Obama read from the letter in his speech.

I recently received a letter from a woman named Jessica Sanford in Washington State. And here's what she wrote: "I am a single mom, no child support, self-employed, and I haven't had insurance for 15 years because it's too expensive. My son has ADHD and requires regular doctor visits and his meds alone cost $250 per month. I have had an ongoing tendinitis problem due to my line of work that I haven't had treated. Now, finally, we get to have coverage because of the ACA for $169 per month. I was crying the other day when I signed up. So much stress lifted."

But Sanford's story doesn't end there. As CNN's Jim Acosta reports, thanks to a series of glitches, Sanford's insurance premiums turned out to be far higher than she initially expected:

After Obama mentioned her story, Sanford started having problems. Sanford said she received another letter informing her the Washington state health exchange had miscalculated her eligibility for a tax credit. In other words, her monthly insurance bill had shot up from $198 a month (she had initially said $169 a month to the White House but she switched plans) to $280 a month for the same "gold" plan offered by the state exchange. Sanford said she was frustrated with the state's error. But she decided to purchase the new plan and thought everything was fine.

It didn't end there either. Eventually got a second letter from Washington's state-run exchange. That letter, according to CNN, stated that "there had been another problem, a "system error" that resulted in some "applicants to qualify for higher than allowed health insurance premium tax credits." And because of that error, Sanford would have to pay more still:

The result was a higher quote, which Sanford said was for $390 per month for a "silver" plan with a higher deductible. Still too expensive A cheaper "bronze" plan, Sanford said, came in at $324 per month, but also with a high deductible—also not in her budget. Then another letter from the state exchange with even worse news. "Your household has been determined eligible for a Federal Tax Credit of $0.00 to help cover the cost of your monthly health insurance premium payments," the latest letter said.

Sanford, who is self-employed, tells CNN that she now plans to avoid purchasing health insurance entirely, because it's simply not affordable on her budget.

It's worth highlighting the fact that this occurred in one of the 15 state-run exchanges that is supposed to be working better than the federally facilitated system covering 36 states. Indeed, Washington state's exchange has frequently been touted as one of the systems that works the best among the state-run exchanges. But those reports tend to focus on the consumer experience—the ability of a user to smoothly navigate from start to finish in the insurance enrollment process. Yet as Sanford's story shows, a smooth process can still be frustrated by inaccurate pricing and subsidy information. The same, naturally, would be true of incorrect enrollment data being sent to insurers, another problem that's apparently pervasive in the federal system.

Sanford's story illustrates how some the Obamacare stories that might initially look like successes might not be once the data and pricing issues are all sorted out, and offers a reminder that sometimes the process of getting things straight can take weeks. That's why we ought to remain skeptical about the White House's push to improve the enrollment experience for the "vast majority of users." It's not just the user end that's broken. And even if the website works well enough to allow most people who want to enroll to get through the process, there's no guarantee that it will continue to work once they're inside the system.