Stress Coat VS anti-stress - same thing ?

I had inserted my fish from the old tank to my new, i thought since its
cycled it should be ok, but i apparantly ran out of anti-stress.

So i went the other day to buy some, and the guy at the store gave me a
stress-coat, i told him since the fish look already abit stressed,
shouldnt he give me anti-stress instead of stress coat... he said no.

while the coating sounds nice as prevention to sickness at times that
the fish are stresed, wouldnt anti-stress lower the stress itself and
let them build back their immune system, im afraid that if they are
already sick, the coating will not be that good as stress stays hig ...
is that true ?

thanks
LT.