From my recent interview experience I can confirm that a) having a re-entry permit does not preserve anything (I had 2 7-month trips and they were seen as breaking my residence) and that b) you will have to prove that you have have your primary abode in the US. For me, the IO did not accept tax returns, retirement account statements, etc. He wanted to see phone bills, car insurance, recent bank records showing residence activity in the US. I was able to provide those for the required period and was approved. The IO in my case did not look for a pattern in my travel (I had a bunch of back to back to back trips including the 2 7-month trips) but he verified the number of days outside of the US and the fact that I basically stopped traveling in early 2007 (had two foreign trips of 1 week each in 2007-2008).