I-140 & I-485 filed concurrently. Is CP advisable now?

[Hal2010]

I-140, I-485 filed concurrently in Nov 2002. I-140 Hopefully approval is expected by end of this month May 2003.
Also applied for EAD as H1B is expiring in Sept 2003.
Is CP advisable now after I-140 approval? i.e. withdrawing I-485 and opting for CP.
About how long it might take for CP interview, if I am to opt for CP now? Mumbai dates show current. Please advise. -----Thanks lot.