As a part of the health care reform 2007 the German risk structure compensation scheme was extended so as to connect the financial cash flow towards the payers to morbidity information from ambulatory care. Within this context, morbidity information consists of prescriptions as well as coded ambulatory diagnoses. Accordingly, a high quality of coding is essential for a morbidity compatible allocation of funds. The aim of this study was to evaluate coding quality via qualifying characters as well as to identify future challenges. It focuses on diagnoses which are qualified as "assured" or "post-treatment" from about 350 million diagnoses of about 11 k practitioners' treatment of 2.7 million AOK PLUS insurants in Saxony and Thuringia during the years 2007-2010. The practitioners' documented diagnoses were aggregated within several groups according to the code of specialisation which is attached to the practitioner's 9-digit lifelong identification number (LANR). As a result, the number of "assured" diagnoses generally rose from year to year. Furthermore, diagnoses marked as "assumption" or "exclusion" remain constant over time. We identified a lack of diagnosis coding precision regarding the condition after certain medical events. In particular, general practitioners tend to use diagnosis codes qualified as "post-treatment" instead of using correct "assured" diagnoses qualified for conditions after certain events. Consequently, we expect adverse effects evaluating the cost of diseases as only "assured" diagnoses are considered within the risk transfer compensation scheme.