Although she has not examined this client's particular case, your manager confirms that it is likely that an internal reconciliation issue is impacting what the client sees. After speaking with the client, your manager asks you to examine the case in more detail. You find an internal cash booking error; the figure should be $1,000, but is $900 on one system. There are several possible causes, so you need to prioritize the order in which you explore each possibility to determine what happened.