Don't mix different variations of cards together in sales data
All sales are aggregated into a single total. For instance, when examining the sale history of a Joe Burrow base card, it includes various types like prisms, refractors, and different variations all grouped with the base card. This mixture impacts the estimated value assigned to that base card. It would be better to separate them according to their specific card types.
This Joe Burrow base has multiple parallels mixed in with its sale history...it's crazy..
https://www.sportscardspro.com/game/football-cards-2020-panini-prizm/joe-burrow-307
I looked through that page and only saw 1 sale that was for the SP card instead of the base. All the others seemed to match correctly.
Maybe another user cleaned it after already. If the listing doesn't say what variation it is, we won't be able to match those correctly.