I am a bit surprised by the advice to do a sudden change instead of acclimation.
Acclimating: You are leaving it in toxic water an extra hour or two, which gets diluted as you acclimate.
Assuming 18 hours or so to ship, that is really only 5%-10% longer.
Immediate transfer : You might be treating it to some very nasty transitions.
PH could be way off, especially if bag was just opened to fresh air.
Temperature was stated as being way off.
Salinity will likely be very close on a reef product, but still off a bit.
Edit : Slow week at work with the holidays coming up. To much time to think about things.