Regarding JSB label, Air Arms label, or FX label...my experience has been that I have about equal odds of getting a good batch.
Or in other words, I wouldn’t hesitate to buy a few tins of the FX 8.4 from Trenier at $12 ea. Still slightly cheaper than Pyramyd’s inflated buy-3-get-1-free gimmick, so the freedom to mix and match as you please without having to play a game to maximize the value.