visa bulletin 日期意義 - 移民

我現在準備遞交I-140

之前(Nov 2015)和律師請教visa bulletin日期的意義
看不太懂律師的回函

On the Visa Bulletin, the priority date is the date that the PERM was filed
with the Dept. of Labor. There are now two charts on the Visa Bulletin –
one which tells you when you can file (Chart B) and one which tells you which
priority dates are being issued green cards (Chart A).

You are in the EB-3 Category, All Nationalities, with a priority date of
August 8, 2014, so at this time your case is eligible for filing, and
eligible to have the green card issued once USCIS has completed processing.

但是依照最新的visa bulletin EB3 的日期是 01OCT15
那這個日期的意義是什麼? 為什麼律師會說Aug 2014 又說我已經可以遞件?
這個遞件指的是I-140 ?

之前爬文，485要等140審過之後才會開始沈
所以同時遞交I-140 和 I-485 或是等到140批准後再遞交485有差別嗎?

謝謝

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