>> Does any one has idea about how NSC is processing pending & retrogressed I-485s?
It is common understanding that petitions that were effected from Retrogression(Cases that would not be considered for Adjudication untill their PD beocme current). that doesn't mean service centers completely stoped and not going to touch, service centers are processing normally as they are publishing their processing dates and any case that submited before their published date will be considered as active case, and only including FP+RFE+Adjudication review+all other requirement beofre adjudication will be perform normaly only thing is that case will be put on hold untill PD become current.
Also all cases have their own periorities and they calculated months before the case is actually touched/active.
>> Can we expect the automatic-approval once the PD crosses the cutoff date?
All cases are search/review/line-up based on their periority every month before new bulletin is issued. or in simple way to understanding cases that were gone thorugh all FP+namecheck results/bk-check+RFE+other requirement and ready to adjudication and put on hold becz of PD are kept in seperate shelf. so they are not missing your case, even they are not in shelf they do have in their system.
If u are interesed more detail, You may wish to read "Standard 485 Procedure" PDF doc that link I posted many times(try to find if not post again I would try to search that link). And all other Service centers update bulletins/guideline that are pubklished and posted on diff immig related websites.
Good Luck
