A lot of sellers adjust bids without first checking where the sale actually came from.
Amazon PPC performance can vary heavily by placement:
Top of Search
Product Pages
Rest of Search
If Top of Search is converting profitably, it may deserve more aggressive bidding.
If Product Pages are driving cheap conversions, they may deserve their own strategy.
If Rest of Search is spending without results, it shouldn’t keep getting the same treatment as profitable placements.
The takeaway:
Don’t optimize one average bid for three completely different placement behaviors.
Better PPC decisions happen when you manage bids with placement level intent and performance in mind.