Dual r3 calibration does not work correctly

I bought 3 DUALR3 to control roller blinds and found a big flaw in the device itself. The engine calibration is not carried out in the correct way for greater versatility. I use a homemade curtain drive. The time for raising and lowering the curtains is different due to the lack of maintaining the same motor speed when raising and lowering the curtain. And the manual calibration of the engine itself, as I understand it, is read from the lowering readings for lifting and vice versa, shown for lifting are read from lowering readings. And due to the fact that the speed of ascent and descent are different, the calibration does not work completely correctly. It is necessary to change the reading algorithm for engine calibration for adequate operation!!! It is necessary to read the readings separately for raising and lowering the curtains. Maybe the best solution would be to provide manual input in seconds for raising and lowering the curtains, but not lose the ability to open and close in %. Please convey this information to sonoff developers