This is how it works

If the hero being transferred from has
1-7 stars
The new hero recieves 1 less star then being transferred
8-9 stars looses 2 star levels
10+ stars looses 3 star levels

If the hero being transferred form is a
Saint
the new hero looses 1 sainting level
if it is Half angel it looses 2
Angels loose 3
arch angels loose 4
dominions loose 5

So regardless of the what saint and stars the receiveing hero has

A half angel 5 with 7 stars transferes to a half angel 3 with 6 stars
a archangel 3 with 9 stars transfers to a angel 4 with 7 stars