Dave81644, thanks for the clarification. Your findings seem to match my experience in general.
Regarding the dull surface soaking oil, yes, they do, but oil on the ball cover is not the same as polish (as you know). Polishes tend to clog the pores to varying degrees, which creates skid and eventually more snap on the back end. While a ball finished at 2000, or even 4000 without polish will tend to read the pattern more accurately. I find with heavier or longer patterns I like to "blend" out reaction both side to side and front to back so I lean towards the non-polished finish for my game.
Neither side of the coin is necessarily "better", but the one that matches with your game and oil pattern should be used. Keep one ball dull, one shiny, and a spare ball with you to keep your options open. Best of luck.