We all think our business processes are unique and proprietary. And in fact, they are. But utilizing off-the-shelf software makes customizations critical to ensuring that the software fits your needs. The software should change to the way you do business...not that the business should change to the way the software works.
The critical success factor for customizations is what happens when you upgrade? To ensure that the customizations do not "get stepped on," the architecture needs to take the upgrade process into consideration.
Epicor, SAP and Microsoft have taken the upgrade process into consideration. As Grey Wolf develops your customizations with DynaChange, Crystal Reports and SQL Server; you can be reasonably assured that newer versions of the core software will not cause major disruptions.