Use the result as a scenario, not a black box
The result is intentionally a planning estimate rather than a fake engineering model. Electrical equipment becomes heat in the room, and people add additional sensible load. The safety factor gives you a way to test how much headroom you are carrying before a professional accounts for envelope heat gain, outside air, latent load, duct losses and equipment performance.
How the math works
Electrical sensible load = total equipment watts × 3.412. People are estimated at 400 BTU/h each for planning. Base BTU/h = equipment heat + people heat. Design load = base load × (1 + safety factor). Cooling tons = design BTU/h ÷ 12,000.
If lights and equipment total 7,200 watts, that electrical load alone is roughly 24,566 BTU/h. After people and a 20% planning margin, the design estimate may move well above two tons before latent moisture and building-envelope loads are considered.