Submitted both EB-1A+I485 and NIW alone on Sept 26 to TSC. NIW was fast, approved in 10 days, then received official FP notice after another 10 day, then just received EB-1A approval letter issued on Oct 26.
It looks like the official FP notice may hint for an intended approval - just guessing, not sure if that is truely the case.
Thanks everyone who shares his/her experiences and advices here on this board. Lots of those information are very educational.