i asked hdb about something similar. they said if by the 2nd HLE assessment period, your income exceeds 10k, they will re-assess on a case by case basis on whether you can still get the HDB loan. i'm guessing if not eligible for the HDB loan, you might have to consider a bank loan, which can still be paid through cpf. you could try asking them, but they did not seem willing to reveal much, and just said it's on a case by case basis. i guess they did not want to tie themselves down to a definite answer.
