Well, I am not an expert on this matter, but what I was told by a friend was as follows. If your current salary is less than the salary filed on labor, USCIS looks at company's financial status to make sure company will be able to pay you that salary when the green card is approved (As the salary mentioned on labor application is the one that company promises to offer you once you are ready to accept permanent position...green card....as your current employment offer is not considered permanent offer as you can't stay beyond 6 yesra of H1B)...If company hasn't submitted its annual statements with your application, an RFE may be issued for ability to pay......just to varify that company is making enough profit to be able to pay you that difference after green card is issued. Hope this helps