skull level and exp

[tmdsod]

When my alt is killed after tagging a mob that looks like a skull level, can't I get full experience?
I just level up my alt to 38.
I know that it is mean that my main character can help alt (previously I only used my main character's pet. It was very fast but slowing down. I just needed 26 hours of play time)
but I'm worried that my plan is wrong.
Previously, when I experimented, my character gained only a small amount of experience from a mob at the skeleton level.