Framer, it is time to admit you are wrong, instread of digging up more and more obscure arguments as I shoot down your previous ones...
So far you have now admitted, that everything I have posted so far is correct. Min drag = min thrust required = cost index 0 (no wind, as I wrote already in the first post mentioning cost index 0).
So I is really time to let it rest.
LRC is pretty much irrelevant in today's CI environment
Yet this is the speed Boeing uses to calculate the thrust limited altitude. Like I have now written several times, this gives you an extra margin.
About the last non-sense you posted, this is basic ATPL knowledge:
The lower limit you suggest is the top of the lower amber band, whereas the lower limit should be min drag speed.
No, this is the lowest speed that should be used as cruise speed (the selected cruise speed). Because a speed lower that this speed is ineffective.
As you quoted
Normal flight (faster than L/D max) is inherently stable with respect to speed.
(hope my formatting stays, because it dissappeared from my previos posts, the emphasis should be on NORMAL)....
any disturbance causing a decrease in airspeed will result in a further decrease in airspeed unless thrust is increased.
(emphasis "unless thrust is increased")
So it is quite obviuous that we should not plan to fly at a speed lower than L/D max (Max range cruise = cost index 0 (no wind). And we don't.. we always plan to fly faster that this speed, because...
due to the inefficiency and inherent instability of the slow flight speed range.
It is inefficient, because we have a higher drag, and fuel flow plus we will have a lot of throttle movement to maintain the speed.
That all together means that if you cruise at a faster speed, a temporary excursions into this regime is acceptable, but must be corrected by increasing the thrust (pretty obvious - the "unless thrust is increased" emphasis).
We will always cruise faster than MRC, because it makes no sense to cruise with a lower speed. And should the speed temporarily go below MRC, towards the top of the amber band, we will correct it (auto throttle too).