Hopefully, you are not too bogged down with the DFD. The owner and store manager met this morning and came up with some new rules that will need to be implemented in the SIM system:

The owner and store manager have decided to offer customers a service plan were they pay a flat rate once a year. With this plan, customers only pay for the cost of parts when they have their appliance(s) serviced. They can only buy a service plan if they have purchased an appliance from Appliance Warehouse.
With this new service plan, if they have service on their appliance more than 3 times during the year, they will have to pay the full amount of the service fee and cost of parts.
If the customer does not buy a service plan but buys their appliance from us, we will give a 20% discount off the service fee for the life of their appliance.
Everyone else will pay the full cost of the service plan and parts cost.
Create a decision table from these rules. I would like to see your first pass at this by our next scheduled meeting.