Go to www.lianglaw.com to see a post regarding the risk of filing I-140 and I-485 concurrently (I'm not advertising). If you have a legal non-immigration visa, and are not worried about losing it, why not do 140 and 485 seperately? I-485 is very easy to do it by yourself, you don't really need to pay the lawyer for doing it. But if you're confident that your 140 will get approved (unlike NIW or EB-1), then do it concurrently to take the advantage of it.