Why sunni scholars say that shadow for asr time should be measured with addition of zenith shadow of same object?

Question

Scholars say zenith shadow length of object should be added to 1 height of the object to get Asr time's, but in the texts of Hadiths' it is only 1 height of object, without addition of its zenith shadow length.

It seems to me that the rulings of the scholars contradicts narrations, can you clarify how the scholars came to this ruling?

example of what scholars say:

shadow of each thing is equal to twice its size excluding the fay' (shadow) of decline

by "shadow of decline" they mean shadow of of same object as it was at zenith time. this is Hanafi text, but same thing in all 4 sunni mazhabs.

Answer 1

Zuhr's time starts after the sun has declined from its zenith (Zawal), and Asr's time naturally starts after Zuhr.

The issue is that the length of the shadow cast by an object varies with location (longitude\latitude) and the seasons (summer\winter).

There are places and times where the minimum length of an object's shadow (at the Sun's Zenith) is equal to or longer than the length of the object.

For example see this location in Australia, where the minimum length of the shadow of an object today is 1.02x its size at the sun's Zenith. And this location in Turkey in winter, when the minimum size of the shadow at the sun's zenith will be 2.01x its size.

This means that if the hadith are interpreted to not subtract the length at the zenith, then Zuhr's time would literally never arrive in a day and Asr's conditions will be fulfilled at Zawal.

For this reason, the hadith are interpreted to implicitly subtract the length of the shadow at the sun's zenith.

For reference see: Radd ul Muhtar (arabic)