Your conclusion directly contradicts the Code you quoted.
From the Code:
>Whenever the President determines that all or part of any budget authority will not be required...or whenever all or part of budget authority provided for only one fiscal year is to be reserved from obligation, the President shall transmit to both Houses of Congress...
The operative phrase is "Whenever the President determines".
However, your conclusion adds:
>The executive is completely within its power to halt discretionary grants or expenditures during the audit process.
The Code says nothing like this, instead, explicitly stating "on determination", not "after action".
This "prior notification" requirement is also both within the letter of the original appropriations process, and the intent of the law overall.
From the Code:
>Whenever the President determines that all or part of any budget authority will not be required...or whenever all or part of budget authority provided for only one fiscal year is to be reserved from obligation, the President shall transmit to both Houses of Congress...
The operative phrase is "Whenever the President determines".
However, your conclusion adds:
>The executive is completely within its power to halt discretionary grants or expenditures during the audit process.
The Code says nothing like this, instead, explicitly stating "on determination", not "after action".
This "prior notification" requirement is also both within the letter of the original appropriations process, and the intent of the law overall.