Hi Mark,
The EEPROM storage addresses have histories. KD8CEC's software for v5 has a bunch of other features and settings, so the location of the keyer config made sense when it was added, but was left in place when ported for compatibility.
The master cal value could probably be limited, but since that value depends on the oscillator feeding the clock generator, unless you know the tolerance of that part, it's hard to say what the min/max should be. Especially since some home brew folks source different speeds.
Reed
