LFS=Local Fish Store. You don't need to acclimate shrimp for 6 hours, I mean seriously, who has pateince for that!!
I just added 2 peppermints yesterday, acclimated for 20 minutes, dumped them in, they're happy. This LFS keeps their water pretty close to mine, so temp is pretty much all I worry about.
A good indicator is when adding tank water to the holding bag/container, if I see any "swirling" (indicating a big difference in salinity and/or temp) I take a bit more time. But not 6 hours!