Does owning the Buy Box guarantee sales?
Owning the buy box does not guarantee sales, and depends on the rate of sales (SAS does not know this before it happens - the figures shown are just estimates).
For example, if the buy box analysis were to say a seller won 47% in a 30-day period, that's interpreted as them winning the box 47% of the time during that 30-day window - it has nothing to do with sales.