Hi Ginnu,
I've the same situation though my second labor is still pending and my I-140 and I-485 was filed after first labor approval.
I wonder if filing two I-485 as you explained above is better or going for CP with the second labor?
-----------------If you have earlier I-485 still pending you cane file for new I-140 for CP or file for second I-140 and second I-485 and if second I-140 is approved while earlier filed I-485 IS still pending when you get your new I-140 approved you can attach that I-140 to pending I-485 because it will have earlier PD, if it is denied then second I-485 will be the base of approval.
Or you can file I-140 and once get the receipt of I-140, inform the BCIS whre your earlier I-485 is pending and can request them to interfile that I-140 with pending I-485,( here risk is if you have any RFE for I-140 much better if you send the I-140 approval copy to be attached to your pending I-485
What are the advantages?
---------------- With second I-485 filing you have the advantage of the earlier I-485 PD and case can be approved and it will take same time as for CP because your I-485 is still pending and other benefit is that if anything goes wrong with I-485 lawyers can handle the process in US
Disadvantages?
If CP rejected no appeal if I-485 is denied one can go for Motion to reconsider and appeal, with I-485 pending you can use AC21 but with CP no AC21