VA Disability & Activation

When you get activated from what point onward will you have to pay back your monthly VA check?

As an example, if you go on orders on March 30th and if you receive your VA Disability days before your orders start, will you owe that back?

Another example, if you come off orders before the end of the month, would you be clear to keep that VA disability check, or will the VA collect that one back too?