PSA SMR question

[JollyElm]

Here's a question, if anyone has some insight...

How truly accurate are any of these sites, including SMR? Over the past year or so, quite a few cards I bought have curiously never appeared in the PSA 'Auction Prices Realized' site (the only one I consult aside from the sold results on ebay). These buys were either when I negotiated a price with a seller and he sent me an official offer (so nothing nefarious was involved), including a 1964 'Koufax Strikes Out 15' card, and a few others where the title of the auction had the wrong year listed. For instance, I recently bought a 1962 card in an ebay auction that was listed as a 1959, and a 1972 Wilt Chamberlain that was listed as a 1974. These cards are nowhere to be found in either the right or wrong years on the PSA site, so my assumption is they just receive the official data from ebay and if the year/player/card number doesn't correspond to reality, they are just excluded (garbage in, garbage out). Is that most likely the case? Do any of these sites do deeper dives into the data to make it more accurate overall?