I hope I am answering this per your question.
I was told by week 10 I could go off, but kept going through week 12...as I still had the PIO and enough Crinone for 12 women.
I would definitely have your RE test your P4...and self monitor if the RE feels the level is fine, but you do not.
My levels were seemingly low for what most women on this board shoot for. The RE felt it was just fine...so I upped my dose a little.
When I went to see my OB at week 11, I told her I was continuing it through week 12..and she was fine with it.
The women on this board know their stuff. Sometimes I find REs to treat everyone the same..and sometimes WE are not. Go with your gut, question and ask on the board for advice to any of your concerns.