Chronicall Version 3.8 allows you to add as many Account Codes to a single call as desired. Each Account Code you have will appear below the Account Code entry box. To remove an account code, perhaps due to a typo, simply hover your mouse over the account code and click the incorrect account code. The resulting data will then appear on Account Code reports as expected.
You can also enable Free-form Account Codes. Free-form Account Codes allow you to enter a new account code that was not previously created or assigned to the agent. Enable this within System Settings > Agent Dashboard by setting "Free-form Account Codes" to True.