My labor certification was filed in April 2010. I got approval and the company is looking at filing the I140. Starting July 2010, I am being paid higher than the prevailing wage.Since ability to pay has to be proved from the priority date (April 2010), what documents are required?

I work for a small company (8 people) and my company 2009 tax documents will not be ready till mid September. Is it better to wait for 2009 returns before filing? I am eligible for concurrent filing so I could get AP and EAD sooner if I file now. I think 2009 tax returns do not prove the ability to pay but will probably prove that this is an established company. I was paid lower than prevailing wage in 2009.