I keep getting the answer $107.79 for the Actuarial method. In the book it says $41.29 for actuarial and $39.70 for the rule of 78 method. Could someone please explain what I am doing wrong?

The problem states each loan was paid off early and to find the unearned interest.Here is the problem.

Amount financed is $3310, regular monthly payments are 201.85, with 18 payments scheduled. There are 6 remaining payments scheduled after payoff. I think the last part is what is tripping me.