Difference between exp/h with guides

Hi there,

Last week we saw a duo hunting at fire library and hitting 9,4kk/h with charms on book and squid, the ek didn’t have bis items except souleater.

Yesterday we tried it, we also got the same charms and have bis slots and the exp we got was like max 7,4kk/h.

Can someone explain why the difference is that big?

Thanks in advance,

Greetings