I apologize for not having more time, perhaps to dig up some of my old data. However the methodology went something like this. Equipment + Install + Configuration + User time cost + Time cost for upgrades, maintenance, and expansion/changes. Assuming you have an average size small business. In that small business you have ~40 phones and 50 employees. Each employee gets their own did. ~5 phones are "executive" (fancier model) and you have two which are for receptions. The receptions will monitor one of three "main" incoming lines and will need to know which one has been dialed before they answers. Similarly you will need 3 different dial by name directories which may or may not have some overlapping people. Each person needs to be able to switch between 3 preprogrammed settings on how their calls are handled. Integration with their business calendar so the phone system automatically switches between several settings depending on the individuals availability (in a meeting, out of office, etc.) is a big plus (ShoreTel does five settings as a base and was expandable but their was something about the expansion that I can not remember. ShoreTel also did the integration with Outlook, Lotus, and a half dozen other applications calendars out of the box,