Jean - I won't hazard a guess/opinion as to relative costs of NC vs EBOM (I think these differ radically from project to project and building to building, and it's probably not helpful to even theorize), but I do think its important to note that even though the marketplace may presently perceive a LEED plaque as a LEED plaque and not fully grasp the distinctions between rating systems, the differences from a user/owner perspective are substantial. An NC plaque says something about the design of the building and the construction of the building - but nothing about the function. EBOM is the inverse - it speaks only to the function of the building (over a discrete period of time) and says little or nothing about design/construction. Also, you'll note that an NC plaque is forever - once D&C is done, that plaque is permanent. An EBOM certification represents a finite time period. So one might argue that an NC certification says less about a building but for a longer time, while an EBOM certification says more about a building, but for a shorter time. Although there would probably be a lot of reasonable counterarguments to that sentence. . .