These two metrics are calculated differently and cannot be compared directly.
Amazon's Featured Offer Rate
Amazon defines the Featured Offer rate as follows:
The Featured Offer percentage is calculated as the total page views in which you are the Featured Offer divided by the total page views received by the products you list. Only active items are considered.
The Featured Offer rate considers ASINs with page views and ignores those without page views for the selected time period.
The Featured Offer rate looks backward and examines past performance. It does not reflect the current buy-box position.
MS BuyBox Win Rate
By contrast, the BuyBox Win Rate measures what percentage of your offer SKUs are currently winning the buy box.
It reports in real-time and is forward-looking in nature.
In other words, it answers this question:
If a buyer would visit my Product Detail Page right now, would my offer SKU win the buy box?
Amazon pushes an alert to MerchantSpring instantaneously every time a change to an offer for an ASIN is detected.
In a scenario where the buy box is lost, this forward-looking metric allows the user to take action before a sale is lost to a competitor.
Amazon's Featured Offer rate and MerchantSpring's BuyBox Win rate are two distinct metrics that cannot be compared.
The Featured Offer rate reports historic performance based on ASINs with page views. By contrast, the MS BuyBox Win rate considers all offer SKUs and provides a forward-looking view in real-time.
Featured Offer Rate
BuyBox Win Rate
Products with page views
All active offers
24-48 hour delay