I am trying to formulate a theory to support your last part Q, as well as credit to Teddy on a conversation I had with him earlier today, and by this attempt to formulate a theory, try to explain the incredible phenomena of the Oct VB in which people are also getting green cards, not just date movement. Assuming by law, DOS
can only give 27% (is it 30%?) of all visas available in a category in the first three quarters max., following would be availability:
EB1: 10810 or 3603 a month
EB2: 10810 or 3603 a month
EB4: 2683 or 894 a month
EB5: 2683 or 894 a month
Total: 26986 a quarter, or 8995 a month
233 a month is already the normal quota for EB2IC.
Each month USCIS fails to produce adequate demand of non EB2IC, the unused numbers are given to EB2IC. This is monthly spillover, not even quarterly spillover, lets call for argument sake. Or at least if quarterly only, then each quarter, similarly all remaining is grabbed onto EB2IC. What has happened this FY 2012 so far, however, almost looks like monthly spillover, it is not QSP.
Now say DOS wants to always maintain a inventory of 20k (assuming 7k approvals of non EB2IC as worst case) to always remain ahead of the curve of 27k a quarter, hence the intent of keeping on moving dates. Anytime USCIS presents a substantial non EB2IC demand, or DOS feels they obtained 30k inventory, which is higher than the 26986 max a quarter, they pause or adjust the pace of the movement, cleverly done and based on amount of non EB2IC demand presented by USCIS, they might not even need retrogression. This way EB2IC keeps moving, inventory keeps getting built up, and based on non EB2IC demand by USCIS, adequate congestion control is done, any bursts of non EB2IC are accommodated and when the bursts go away, again same EB2IC picks up steam. It is a fair system IMHO. Visas are not wasted, current categories remain current, laws are followed, there is no mad rush anytime, EB2IC is not penalized for USCIS's failure to process other categories backlog consistently and then by them making up for it suddenly in last quarter like they did in last FY August. If they are applying this to EB4 and EB4 demand then keep in mind, this also takes away the possibility or at least reduces by great deal the quantum of EB1 backlog reduction cannibalizing EB5 and any possible EB4 SO from coming onto EB2IC.
this idea may be totally not right, but there might be some form of at least QSP in play to explain. only those who try, may fail, tear apart as you like
