Again, it all depends ... on the basis for the sums.
Not speaking to any particular Type/Model here but, generally, the AFM provides a range of bases for takeoff calculations. There are three main areas of calculation -
(a) general takeoff charts for cockpit use will be constrained significantly to reduce the number of flexibility options. This has nothing to do with whether pilots are clever or not .. simply a case of keeping the exercise simple to permit a quick and dirty (but acceptable and safe) calculation to permit the operation to depart without too much delay.
(b) manual calculations by an ops engineer may be quite complicated (if the runway is commercially important) or fairly constrained (for standardised operations or a sensible balance of back room time and cost). Not many folk have to bore themselves with this these days, given the ubiquitous extent of capable PCs and other computers.
(c) a full computer analysis will exhaust all the nuances of the AFM to extract the very last kilo for the operator .. and all done in a few blinks of one's eye. (Note that setting up the program will be a long-winded exercise unless the OEM provides it to the operator)
As to the ASDR, again it depends on the basis for calculation. One of the main concerns of effect will be the selection of V1/VR, presuming that is provided in the AFM data.
If the ratio is kept sensibly similar througout, and in the absence of overspeed schedules, then one would expect the selection of a higher flap setting to result in a lower V1 and a less critical ASDR.
The specific data you are looking at is inadequate to draw much in the way of conclusions as the basis for calculation is not disclosed.
I would suspect a case of comparing apples and oranges resulting in considerable head scratching and confusion.
On another point, having scanned through the thread, is the following comment -
The shorter your t/o run you get airborne at a lower speed. That kills your climb cause you have to accelerate much further towards best rate of climb speeds than if you got airborne with zero flaps for example.
The first observation (presuming min speed schedule) is correct as the selection of flap and speed schedule initially is driven, inter alia, by runway length.
However, the basis of takeoff certification calculations is that V2 is the target (OEI) and there is no airborne acceleration permitted other than that associated with the rotation phase which provides the VR to V2 increase. For AEO takeoff, the technique is such that the flight path is constrained to remain above the OEI flightpath. While that generally sees some acceleration, there is no specific intent to accelerate to achieve a better rate of climb.
I suspect that the poster's comment was directed at some aspect of light aircraft operation rather than heavy iron.