So when calculating the Allowable Exterior Lighting Power for your Baseline energy model, there are Tradable Surfaces and Non-tradable surfaces. My question is concerned with how LEED handles lighting on Non-tradable surfaces.

It's my understanding that allowances for tradable surfaces are such that if you over-light a parking lot, you can make up for it by under-lighting a canopy. You also get to take credit for good lighting design if the sum of your installed lighting on tradable surfaces is less than the sum of allowable lighting per 90.1 table 9.4.5. For example, if you have designed 10 kW of lighting, and the allowable lighting power is 12 kW, you can show 2 kW of savings in your energy model.

For non-tradable surfaces, ASHRAE 90.1 says that you cannot compensate for overlighting a building facade by underlighting a loading dock for ambulances. I have no problem with this. What I have a problem with is the LEED Credit Form saying "Values [for Non-Tradable Surface Exterior Lighting Power] should be identical in the Baseline and Proposed Case." In other words, if a project uses super-energy-effienct lights to illuminate a building facade with 10 kW, and the allowable lighting power per Table 9.4.5 is 12 kW, I CANNOT take credit for this 2 kW savings in my energy model! Instead I have to put only 10 kW of lighting in the baseline case energy model.

This does not seem fair, nor does it seem to agree with the intent of ASHRAE 90.1. Does anyone know the USGBC's reasoning for this?