I had same qty of inventory in July(only few quantities increased in late July of same asin), and till today. Untill July, I paid only $50. Amazon storage fees remains same for same amount of inventory till September, then it increases in Q4 (Oct, Nov, Dec). It should increaase by anywhere between 20%-60%. My fees has increased by 140% in August, and 160% in Sep, Oct. Which is not regular.

Quantity of inventory was same in August, as today. Fees has increased by almost 3 times. $50 to $132. Amazon should refund any additional amount(more than $50) it has charged in Aug, Sep. Oct fees should increase by atmost 60%(which is $80 at max). See the image attached for fees charged.

Thanks,

Pramish M