HS only gives 10% EXP boost?

When training at Death Teddies with my level 56 F/P mage, I get 5200 exp per kill.
When I have my level 81 HS mule to provide maxed HS, the exp I get is only 5720 (+10%), with the HS mule NOT IN PARTY.
Why isn't it 7800 (+50%)?

Thanks.

 

are u the only one in the party?

 

Yes I am, I guess I'll need another low-level mule.

Next time I'll make sure to read it through.
Thank you very much for clarification.

 

Just keep the HS mule in party while grinding and kill the hs mule later before it reaches 99% exp.

 

The problem is not the HS mule leveling, but the exp it gains.

 

Your f/p mage will gain more exp if there is more than 1 character in the same party receiving exp with HS buff.

 

That's right, thanks.