An auction of about 135 foreclosed homes in San Diego Saturday provided more sobering news for mortgage lenders. Ramsey Su, an investor and former real-estate broker who attended, calculated that the high bids for the homes averaged 67% of the prices they fetched when they were last sold, mostly in 2004 or 2005. At a similar auction in San Diego in May, the average was 73%. The auction was held by Real Estate Disposition Corp., Irvine, Calif., which promotes such sales on the http://www.usahomeauction.com Web site. REDC officials couldn’t be reached to comment.