Has anyone else seen dramatic increases in Amazon advertising costs?

Compared to the early months this year, my Amazon advertising costs have increased considerably.

My Average Cost-per-click has more than doubled and my total spend has increased by multiples. My ACoS percentage has also been negatively affected.

I have been using the Bid+ tool (Raises bids in this campaign up to 50% more than your default bid when ads are eligible to show at the top of search results.). I believe that this may be one of the issues.

Has anyone else experienced anything similar?