Let's cut straight to it:

LEED background information:

LEED energy models have a default requirement that process loads and receptacles are 25% of the baseline building costs. The total cost must be identical in the proposed LEED model.

However, this assumption is based on a standard office building. Thus, if the process loads and receptacles are designed and documented (think spreadsheets, or even a basic description), one can use the actual designed loads. This can yield free leed points, bascially LEED plus a little math gets you 2 valuable LEED points.

....LEED + Math = 2 Points!

Example LEED Case Study:

Let's consider a building that has 31% savings on the proposed building over 90.1-2007 building:

Let's say the Baseline utilities are $100,000 annuallu, of which $25,000 is from misc equipment ($75,000 from everything else). At 31% savings, the Proposed building would be $69,000 annually - of which $25,000 is from misc equipment (since by default, it must equal the baseline)

If instead, someone took the time to do it, and the misc loads were documented and that made the price equal to $15,000 in the baseline model, the revised savings are:

Baseline:

$75,000 (everything else) + $15,000 = $90,000

Proposed:

$44,000 (everything else) + $15,000 = $59,000

Final percent savings:

(1 - 59/90)*100% = 34.4% savings

With the extra 3.4% savings. This math yields 2 additional LEED points!

While there are other end effects of the misc load that effect cooling, lower documented loads almost always increase the savings. This is greatly increased if the proposed misc loads can show documented savings over industry standards (ie energy star, but the savings must also be documented)

So why do people assume 25% on misc loads so often?

The receptacles are hard to predict and it's tedious to count all items room by room. However, most projects have some level of detail in the receptacle loads and a little extra effort up front will pay dividends. In fact, if you can make a simple explanation, they will likely accept it. The bottom line is:

NEVER arbitrarily increase receptacles to 25%!