Turtle - yes, sounds reasonable. But I don't know at what point the personnel system will start taking actions to separate you IAW the original end date on your EAD orders. That would be my only concern. All it takes is an email to the Recall Shop to invoke sanctuary. Presumably they can undo anything that the system has initiated by your proposed 5-month point. I wouldn't wait that long personally, but your situation regarding "highlighting for bad deals" is different.

And to clarify something else from your post at the top of the page. You said "will reach 20 yrs AD by the 4 year limit of the program." The 4-yr point is not relevant to sanctuary, only to normal extension requests. If your original 3-yr LPRP orders took you to 18 years and 1 day, then sanctuary would be granted to 20, even though it adds another (almost) 2 years.