Michael,
First, please note that sometimes a tax period can have multiple CSEDs (if there was an additional assessment of tax after the original return was filed, etc.). In order to correct the CSED, we recommend filing a Form 911 with Taxpayer Advocate Service to request the modules be corrected to reflect the proper CSED. In our experience, CSED issues are often the result of the IRS improperly leaving modules coded for a pending installment agreement for extended periods of time, and often after deeming a taxpayer uncollectible. Let TAS to do the leg work on this one!
-Amanda