@yamahap45 PSA assign certification numbers to cards as they register them into their system, not when the card is graded. Basically the first package PSA open will contain lower certificate numbers, regardless of tier level.
You should never pay a premium on brand new set cards if people are calling them the “first graded”, as whilst they may have been the first to appear on the pop report there’s a very good chance they weren’t the first cards PSA came across.
I’d estimate PSA currently has at least 8 million cards in their backlog, which is why the certification numbers are so extreme (52XX vs 63XX).
This happened with me and someone else on E4 recently. I submitted a card as bulk back in May 2020 and they submitted it at a higher tier some time around January-February 2021. They got their card back at the end of May 2021 with a 61XX cert, whereas I got mine back 2 weeks later with a 48XX cert. Theirs was graded first as it was submitted at a higher tier, but mine was registered into PSA’s system months before they’d even submitted their card.