That's why a Republican can get the CBO to say a tax cutting plan will raise govt revenue, while a Democrat can get the same CBO to say that the same tax cutting plan will reduce govt revenue. The Dim always asks the CBO to expect a flat effect of tax cutting, while the Republican always asks the CBO to expect the Laffer Curve to increase revenue.
That's the way it is with anything else the CBO is asked to "calculate".
Watch the imbedded video, you will be glad you did.
This is generally all true, however I believe that they also do an annual nonpartisan report on their own where they will typically describe the ten-year outlook based on three different possibilities (the rosy best-case scenario, the middle scenario, and the dire worst-case scenario).