AOS pending EAD from EB and FB

Hi Guru,
I have a good question. Currently I am working using my EB-2 based EAD which will expire this Oct. My wife got naturalization last week. I'm going to apply for another I-485 family based along with EAD application? Does the new EAD will replace my current EB-2 based one once it is approved since they are from different catogories?
My concern is that my current job is a bit different than my job described on I-140 petition. If uscis issues a RFE, EB-2 based AOS may get denied, so my current EAD will be invalid automatically. EAD from family based AOS doesn't have any limitation on work. However, USCIS won't issue a new EAD if current one is not expired and from the same category (AOS pending). Does anyone know how to deal with such a case? Any good suggestion will be highly appreciated!