To individually control 7 LEDs, it would need 7 independent power channels controlled by 7 pins on the MCU… or a completely different design. The MCU only has 5 usable pins, which are currently used for:
- 1x7135: Low modes
- FET: Med/high modes
- Indicator LED
- E-switch
This leaves one, which often gets used for a 7x7135 channel for better medium modes. Or for measuring battery voltage. Or for another indicator LED color.
There are other reasons too:
- What Miller said about efficiency. Using 1 amp spread evenly between 7 LEDs is more efficient than 1 amp sent to only 1 LED.
- If it had 7 levels, at 1/2/3/4/5/6/7 amps, it would effectively only have a narrow range of medium/high modes. To achieve levels which appear evenly-spaced, the power use ends up rather uneven, like the graph of x**3 instead of a straight line.
- Turning on/off individual LEDs in a 7x SRK would make the beam less symmetrical due to the overlapping reflectors.