Understanding credit and trying to predict how it's going to report a score is very difficult. It seems at time by paying items off it actually hurts more than it helps. One thing I recommend all my clients under similar situations is annualcreditreport.com, there you can dispute directly with each reporting agency any discrepancies that appear on your credit report. It is free for everyone once a year. There are other options as well that I could also recommend. I wish you luck and should you have any additional questions please feel free to contact me. I am a Mortgage Banker and have seen many credit reports in the past and have assisted many people in your situation become buyers.