The efficiency values inside the tool are representative efficiencies based upon inputs from a number of reputable transmitter manufacturers, and confirmed by both published data online and in marketing materials for FM, MW, and SW bands. Efficiencies were provided for pure analogue broadcasting, and pure digital broadcasting and also for previous transmission generations over the past 5-10 years (to account for transmitters currently in use).
Typically this was provided as a small range, e.g. 79 – 84%, a single figure for both analogue and digital use. In digital much lower transmitter output power is required for the same (or – as tests are proving – greater!) coverage, and in AM mode, no carrier is required, which reduces the transmitter power consumption. The tool proves this every time. The difference will be though individual.