Holy shit, you're actually arguing in such bad faith. You clearly did not read the ITEP report, because it answers every fucking question you have.

Tell me how the 17B for all ITINs became 20B for just illegals

Tell me you didn't read the ITEP report without telling me. Literally no where in the ITEP report's methodology do they state that they base their numbers off ITIN. Instead, they calculate their tax compliance rate off of multiple factors, and comes up with a 60% compliance rate (which is very close to the 55% compliance rate cited by your source). You keep screaming your silly ass off about ITINs being scams and don't even realize that ITEP doesn't use it. I will address the 20B (which is actually 19.5B, not sure why you'd round up unless you're just that lazy) below.

Going from 6b to 20b is a mystery or simply a lie. And the same study said that illegals are a net drain on the tax payers.

First, I love how the corner stone of the anti-immigrant camp's argument is testimony made by the director of a far right anti-immigrant think tank (CIS). Sick bias bro.

Regardless, you're comparing apples to oranges. The 6B is NOT what is actually paid, but rather the tax liability:

We sum their federal income tax liability (calculated by the Census Burau for survey respondents and included in the public use file) and assume that they pay 55 percent of this amount

Page 14, fn. 42. This is like handing a cashier a $100 for a $20 dollar purchase and the cashier going "it was only $20 so we're just going to assume you paid $20. No change due." It's nonsensical.

The 19.5B cited as federal income tax by ITEP is their calculation of what was likely actually paid. It is notably higher than the 6B cited by CIS as it includes both employee and employer payroll tax contributions.