after “few days” of delay, I had a moment to look again on my ideas and… solution was really simple, I just have to check all the readouts on meters, and enter everything into “production device”, right now tested on another wemos and looks like it’s working the way I was thinking of.
so, my sensor is connected to D1 pin on my wemos board & is configured as Switch1; then Counter1 is selected on other, unused pin [in my case: D5] - it’s just a placeholder for numbers.
then, in the tasmota’s console, I’ve entered:
switchmode1 1
counter1 <enter-initial-counter-value-here>
rule1 on switch1#state=0 do Counter1 +1 endon
rule1 5
rule1 1
after that, every sensor “blink” [which is understood as toggle: OFF->ON] increases counter1 by value of 1.
so, other way than the standard pulse-count, it counts every blink as one and not as a few or even more like before. I don’t have to save anything anywhere, as the count is preserved after esp reset.
tomorrow I’ll start “daily driver tests” with the right wemos board mounted on water meters and I’ll see if there is any miscalculation with the measured liters.