I think we will need a little more info to help. There may be an easier way to increas your scores. What does your UT look like? Is it under 35%? If so, see if you can get it down to 10%. If it's higher than 35%, then you should try to get it under there if you can. You will see a nice bump relatively quickly by doing that. This is just one example. If you can give us a little more info on the rest of your credit picture, we can make more suggestions.
Also, what CU are you going through that will give you a mortgage at 620? What would the interest be like at that score?
09/28/07 EQ 498 EX 537 TU 477 12/27/07 EQ 526 EX 562 TU 541 02/26/08 EQ 526 EX 589 TU 579 11/09/08 EQ 562 EX 648 TU 578