Singapore Airlines KrisFlyer - F fare basis being booked into C?

I was thinking of purchasing an SQ F fare and was checking a few possibilities using ITA. However, even though the fare basis is F and there is F class availability on the flights I chose, ITA forces me into C or (less often) J. I recall that SQ used to not honor F on aircraft where they have R, but this has since been changed, correct? And at any rate, even on the 77W I am being bumped down to C. Is this an issue with ITA or with SQ?

Without knowing the full itinerary , I can only surmise that it's a multiple sector flight. Ita prices what you may think is a F fare but in fact, it might be a C fare. Unless the is a flight that allows you to book into R class with F fare, it is not a given. SQ have different fares that may not be booked anywhere other than their own website. What you see on ITA are full published fares.

Without knowing the full itinerary , I can only surmise that it's a multiple sector flight. Ita prices what you may think is a F fare but in fact, it might be a C fare. Unless the is a flight that allows you to book into R class with F fare, it is not a given. SQ have different fares that may not be booked anywhere other than their own website. What you see on ITA are full published fares.

Yes, I'm aware that SQ has private fares, but this is the well-known ex-MNL F fare to Canada, which I know should book into F (it did when I booked it last year). The thing is that even if I specify "first class" ITA will only price the C fare, but at a price even higher than the F fare + 25M.