Final Fee Question on this item ?

[fg-militaria]

I have a subscription the $21.95 on a month i sold a book for $13.50 , so my rate for the book should have been $1.23 or $1.24 , its apples and oranges but they charged me $1.62 just tyring to figure out why this happned ? I have been selling on ebay years and have never seen a discrpency before but i dont usually sell books so maybe that is it ? Also the transaction was split between 2 different mounths they won it the last day of number for the item fees were in novmeber and the shipping fees were in December does anyone know what could have caused the extra fees for this item ? I am not really worried about the .40 cents but i am more curious to find out why so this dosent happen in the future on something larger, maybe it was just an error! Look forward to hearing from you guys! 

Final Fee was .96 

SHipping was .66 

Meaning they charge me roughly 12% ? 

Wanted to add before anyone says anything, my account is in good standing with no feedback issues etc, i have also sold a few things since and a bunch of stuff the day before and all of those items appear to be ok fee wise!