Thanks Ustadamirkhan. Looks like the call to KCC is temporarily suspended these days. I always end up with virtual support only when I call to USCIS too.
Also, I had recently filed i-140 for immigration with employment based visa (EB2). USCIS hasn't made any decision regarding my EB2 application yet. I think EDV process is faster than EB2 process. So, I am thinking to stick with EDV at this moment. Am I doing right?