Documenting and automating every minute step of every process in a business cannot be put on a fixed, linear implementation schedule. Unforeseen problems will arise, requiring changes to those business processes and/or the software itself. Sometimes these changes can impact the timeline by weeks or months.
While their analysis is based on the larger Enterprise Resource Planning ("ERP") software packages, the principles are the same for any sized accounting implementation.
In Part 2 (not yet published to the web), they make a point that I would like to amplify: one of the responsibilities of the client is to "appoint a dedicated (and qualified) project manager and steering committee".
If I had to isolate one factor that points to the overall success or failure of an accounting implementation, it would be the dedication of a staff member to the project. Too often I have seen the software project just added on top of the staff's normal responsibilities. The result is that the implementation is sacrificed to whatever is most urgent to the staff member at any given time, i.e. work on the new system stops at month end, budget preparation time, quarterly reporting etc.
If the project is going to involve more than one person from the implementation consultant, the consultant typically appoints a project manager. Even then, the client needs to appoint their own project manager, someone who has the time and authority to ensure client staff do their part. From personal experience, I know that as an external consultant I cannot make anyone do anything on the client staff. I have to work through somebody senior who appreciates the value of the project.
Now that you have a realistic view of what is involved in an accounting software implementation, what if you aren't sure whether in fact you need a new system or not? David Kelly, a contributor to the Microsoft Midsize Business Center has some practical points here.
Bottom Line: if you are considering an accounting software implementation, I would recommend you read these ERP 101 newsletters. If you sell accounting software, I would recommend you get your potential clients to read them. It will help set realistic expecations for the project.