OE allows you to build own distributions, so what you are looking at is two
different distributions based on different different releases but using same
build system ( OpenEmbedded ) over major releases the build system gets
changed too in terms of its metadata as well new features and some old cruft
removed like usual projects. so you have different releases, and different
machines and different distro all contributing to the differences.

Thanks for input from you.
Does this mean shown differences in directory tree is result, a mix of
these all listed parameters?
I am aware of these are two different distributions.
I am aware of these are based on different releases.
I am aware of these are two different machines.
I am aware of release to release to get several classes of modifications.
Actually asked question means how much show differences result from
usage of different YP releases.