Quiet position change on pension

I have a Japanese pension and I did not report value growth since I believe the JP/US treaty allow tax defer on value growth (tax happen to payment only) I did not provide 8833 as well as I was not aware.

Now, my new CPA who is preparing my SFOP is saying that I could be wrong and we are considering PFIC option.

With PFIC, I do not have the need to file 8621 since the balance is below the report threshold and i did not touch the account. Since there will be nothing change to my tax return if I change the Japanese pension position to PFIC, do I need to mention it in the SFOP statement? I am hesitate to say it, because I had EA helped me to file the old tax return but just I follow the 2nd opinion from other people….

Is there any risk involved for quiet change in position?