Congressional Budget Office estimates are funny things. They are usually taken as gospel when they are put out, and ignored later when they are way off. The latest CBO effort related to the Senate Obamacare replace bill is no exception.

Like in all projections, the underlying assumptions bake the cake, and CBO makes a whopper of a mistake right up front when they estimate the number of people who are likely to have coverage under Obamacare after the GOP passes replacement language.

They start with a faulty 2016 baseline that predicts that 18 million people will be covered by Obamacare in 2017, when the people who are actually in charge of tracking Obamacare enrollments, the Centers for Medicaid and Medicare Services, report that the number will be between 10 and 11 million. On the generous side, CBO only missed the correct number of enrollees by 7 million people – oops.

The CMS report unequivocally states, “The average monthly effectuated enrollment in 2016 was 10 million individuals. While effectuated enrollment was over 10.8 million in March of 2016, enrollment had dropped to 9.1 million by December of 2016.”

You read it correctly: in December of 2016 there were only 9.1 million people signed up for Obamacare, and by the end of 2017 this number is projected to increase to just under 11 million people who are paying their Obamacare premiums (rather than a record of those who went to the website but never purchased a policy).

To quote further from CMS they note that in an earlier CBO report in 2017, “CBO revised their numbers down to be more in line with actual enrollment numbers that had been observed in 2014, 2015 and 2016. This adjustment was primarily due to more people maintaining employer sponsored coverage than expected.”

Read that last sentence again: the CBO expected employers to dump dramatically more people into the Obamacare system than actually occurred, making their previous years’ projections wildly inaccurate.

Yet, in the latest iteration of CBO scoring of the Senate health care bill, they somehow seem to have forgotten to look at actual enrollment numbers and defaulted to a faulty 2016 baseline that is 39 percent or seven million enrollees higher than the most aggressive estimates by those who actually do the counting.

Why does all this matter?

Because opponents of changes to the failing Obamacare system are using the fairy tale assumptions of the Congressional Budget Office to contend that millions will be left without health insurance coverage next year, when in fact as many as one million more will likely have insurance.

Incredibly, the CBO even goes so far as to guess that seven million people will flee the Obamacare exchange if they are not compelled to use it through the threat of a punitive tax for not having health insurance.

For once their number might inadvertently be right, since seven million people is also their overestimation of how many people are going to be in the exchange at the end of 2017.

Only in the crazy world of Washington, D.C. math could someone wildly overestimate the number of people to use a program, creating a political firestorm that millions will be harmed, and then through their dire predictions actually get the number of Obamacare exchange users back to the real numbers.

Of course, only in D.C. could the same Congressional Budget Office estimate that millions will leave the free or virtually free coverage that they receive through Medicaid because the IRS says they don’t have to keep it.

But this is D.C., where spending increases are called cuts because not as much money is spent than someone projected, and where seven million Obamacare users are manufactured because someone failed to look at the actual numbers and instead based their entire economic impact analysis on an Obama administration fantasy.

The author is President of Americans for Limited Government