Trying to fill the Investors Bucket

Dear readers,
In an effort to try and fill our Investors Bucket, I visited the Hall of Records for Orange County California, in Santa Ana. I went to the Assessor's office with my MLS for all of the "Cash Sales" within the City of Anaheim, within the last 3 months, which totaled 232 properties. I was directed to one of the computers and told that I could look up the new owners by entering the PPN #, or property address. I was excited to take the first steps towards filling our Investors Bucket list. As I started to pull up the Assessor's Annual Rolls, it was apparent that this was going to be easy......enter the address......get the information........and contact the new owner's to find out if they were potential candidates for our Investor's Bucket. As I was racing along, I noticed an item within one of the "Records" pages. This item was the "Base Year". I asked one of the gals at the Customer Service Counter what does the "Base Year" mean. I was told that this represented the last year the property was sold and assessed by the Assessor's Office. That's when I became confused. If the 232 properties listed in the MLS sold for cash within the last 3 months (Oct, Nov, & Dec of 2011.) then why, during my records search, did the "Base Year" not reflect that? Can anyone answer this question, or do I need to go back to the Hall of Records to get a more definitive answer? Help me please!
Regards,
Scott Hoffman
714-883-2084