That’s pretty normal. My ex worked at congress and she said that most bills are reviewed and changed by lobbyists before they are submitted. And a lot of their changes get adopted almost verbatim. Same happens with regulations.
It was my impression lobbyists usually write the bills themselves. I don't know if this is how it's always done, but my company recently worked with lobbyists and a senators assistant and the lobbyists wrote a paragraph that, once approved by this assistant, went straight into the appropriations bill. Perfect example of pay to play.
Here's a fairly recent example:
> When the legislation that became known as "Obamacare" was first drafted, the key legislator was the Democratic Chairman of the Senate Finance Committee, Max Baucus, whose committee took the lead in drafting the legislation. As Baucus himself repeatedly boasted, the architect of that legislation was Elizabeth Folwer, his chief health policy counsel; indeed, as Marcy Wheeler discovered, it was Fowler who actually drafted it.
What was most amazing about all of that was that, before joining Baucus' office as the point person for the health care bill, Fowler was the Vice President for Public Policy and External Affairs (i.e. informal lobbying) at WellPoint, the nation's largest health insurance provider
...as Wheeler wrote at the time: "to the extent that Liz Fowler is the author of this document, we might as well consider WellPoint its author as well."
To add insult to injury, the same lobbyist was later put in charge of drawing up the rules to implement the law.
>More amazingly still, when the Obama White House needed someone to oversee implementation of Obamacare after the bill passed, it chose . . . Liz Fowler.
https://www.theguardian.com/commentisfree/2012/dec/05/obamac...
Once the implementation rules were set, she returned to lobbying for the health care industry, this time at Johnson and Johnson.
Liberal icon Bill Moyers did a segment on this for his PBS show and it was as close to being openly pissed off on air as I'd ever seen him.