During my interview, US Embassy Manila required me to submit a Certificate of Clearance from Singapore since i lived there for more than 6 months. They gave me back my passport after the interview and told me to mail it back to them once i have my Certificate of Clearance already then they will mail me back my passport with my K1 Visa.(no need to set another interview) Not a bad deal right! BUT the hardest part is getting a Certificate of Clearance from Singapore. They have 2 options, you can order one online just mail them your details, payment and bio metrics from an accredited police office BUT it will take 1-2 months to receive it. Option 2 is to personally go to Criminal Investigation Department of the Singapore Police Force which i decided to do. Its actually easier and faster. It took me 20 business days only.
I mailed my passport and COC to US Embassy Manila via 2go and its free then after a week i finally received my passport with my K1 Visa!