Back in the days of telegrams, NSA was told to stop collecting telegram flimsies for overseas telegrams (Western UInion had agreed to make them available, they were picked up daily then returned).
They said they did but continued the practice. So if Congress directs them to stop doing something, there is no guarantee it will happen.
“The Puzzle Palace” has lots of good NSA tales.
There's a distinct difference here. NSA was told (asked) to quit collecting the flimsies. As I understand the Amash amendment, NSA wouldn't have the cash needed to collect the flimsies.