Errors with Sin City ripping at 50% with NEC ND-3520 and Decrypter

Every time I get to EXACTLY 50% ripping slows to a crawl and I get a constant stream of rip errors. I’ve set Decrypter to reread each error only twice, but at 1KB per error, it’s still damn slow.

Anyone else have this problem? It happening at exactly 50% is kinda suspicious, or coincidence? Brand new disc.