‘P’, the point you overlook is that there is no ‘standard’ flare. Landing is not an open loop step input, but a dynamic reassessment - how goes it, involving adjustment for the start and during the manoeuvre. We learn and improve with practice of how to adjust our inputs during the flare.
Some theories suggest that the assessment involves the comparison of height and height rate, with feed back including pitch attitude, and stick displacement or force. Further moderation and feedback involve time and most important projected point of touchdown.
The Landing Flare of Large Transport Aircraft.
For the OP, if you do not wish to follow the maths in the report, at least scan the many figures at the end which may provide an answer; at least an education every time I look at them.
My safety view is that distance is always a factor, smoothness is just a resultant nicety of practice. It may be easier to gain experience from practice by concentrating on one normal flap setting.