You did a good job of summarizing that paragraph. I think in paragraph 50 we also list the contracts that have been changed to provide flexibility.
All of these processes are legal. However, if the government needs more flexibility in a contract, we still expect it to ensure that job descriptions are specified. It is this lack of detail that has contributed to the fact that it's difficult to know whether the value received for the funds spent is adequate.
These are basic requirements, and they are expected to be in the contracts. They shouldn't be withdrawn after a contract has been issued.