I booked on 4th Jan with SQ on Q & N class and have been able to now choose forward zone seats for free. My booking includes complimentary standard zone as we're travelling with our children but under my KrisFlyer membership on the seat change page (no status) it also says forward zone is complimentary. I can only speculate but this must be to honour previous booking conditions. I've selected forward zone seats in 3 of 4 sectors for no cost. The 4th sector doesn't have any suitable forward zone seats for us.