Serum progesterone help!!

Hey guys. Bit confusing. Wondering if anybody would know what normal serum progesterone would be at 4dpo. I have irregular cycles and I misunderstood when my doctor wanted me to test it. My levels were 14 nmol (I think, I'm in Australia) at 4dpo. I ovulate on day 17 and I think Dr wanted me to test on my cycle day 24 but gave me a sheet that said day 21 (I was distracted but now I do remember him saying to do it on 24), so I tested on 21. (Which would be day 21 for a 28 day cycle). He said the results are low and negative for ovulation but that perhaps I ovulated later and it was still rising as he said it was going up, (I think he forgot I have longer cycles and tested on the wrong day)

So sorry for the confusing question, but just wondered if anybody knows if 14 is good for 4dpo or DAY 18 in a "normal" cycle

TIA