Assurance levels and methods are necessary because each business is different and the level of protection they need will also be different. While everyone wants the highest level of security they do not want to overdo it if the cost outweighs the benefits and underdoing also means the benefits are not there. Systems can fail for various reasons and assurances help a business know that their information is protected and secure despite any flaws or changes.

There is no one specific level of assurance to pick out for all accounting systems, I think it depends on the size of the business. Many small businesses may want assurance levels at least up to EAL3, methodically tested and checked or EAL4 methodically designed, tested, and reviewed. Larger businesses would need an assurance level of EAL7, they need to have their systems tested for effectiveness and to ensure the systems can withstand attacks that could destroy or harm the operating environment.

All accounting systems should use methods that assess the deliverable. It should be assured before putting a system into place that it can work with the environment is deployed to and the flaws have been taken care of. All of the methods are important and should be used when/if available and necessary. Creating a new deliverable for an accounting work place is hard work and making a design that will work within the current environment is always difficult. Of course, knowing how to protect the data within the accounting system is just as important as the design. Without proper security and assurances, the business could lose everything either deliberately or intentionally.