I see on some website advice not to feed Koi an hour before/after dawn/dusk. How much validity is there to this advise. Is there any truth in this thinking?

To me it is clear that most wild fish feed specifically during this period. So it doesn't make sense.

I live in Thailand, obviously hot and I feed Saki-Hikari growth/colour sinking early/late and balance floating during the day a total of 8 times with auto feeders.

Otherwise I monitor TDS and change water very regularly. In water 200ppm, pond around 225ppm and the fish never seen to have a problem and are getting big and fat.

Thank you.