That's a million dollar question even USCIS cannot answer.
I think "priority date" only means that there is a visa available for you when your the time comes.
"As far as your time", USCIS might process according to I485 application date(not good for you) or they might adjudicate I140 and I485 together if all the paper work is available(similar to what happend to October_December '03 filers.................I140 approved, FP sent immediately after I140 approval, 485 approved right away(regardless of 485 application date)).
Although, I hope USCIS continues the later trend, I feel sad for people who have been in the system/process for longer than us.
I think "priority date" only means that there is a visa available for you when your the time comes.
"As far as your time", USCIS might process according to I485 application date(not good for you) or they might adjudicate I140 and I485 together if all the paper work is available(similar to what happend to October_December '03 filers.................I140 approved, FP sent immediately after I140 approval, 485 approved right away(regardless of 485 application date)).
Although, I hope USCIS continues the later trend, I feel sad for people who have been in the system/process for longer than us.