What a 10 actually means
PSA calls a 10 Gem Mint: four sharp corners, sharp focus, full original gloss and front centering within about 55/45. A 9 allows one small flaw. The price gap between the two can be several times over on a popular card.
Same card, different grader
Repack platforms mix PSA, CGC and Beckett slabs. The same card in the same grade often sells for different prices depending on the grader, and platforms that price cards by recent sales account for that. Check the grader on the chase cards, not only the number.
What PSA's submission statistic does and doesn't show
PSA says 90% of ultra-modern sports cards and modern TCG cards it graded since 2018 came back PSA 8 or higher. That statistic combines grades 8, 9 and 10 and does not establish the grade distribution in repack pools. High grades alone do not prove generous pack value.
Check every cert
Look up the slab's certification number on the grader's site and compare the card, grade and year with the listing. A matching record alone does not authenticate the physical holder or card.