The reason behind a longer acclimation period than just .5 hour is due to all saltwater animals having to osmoregulate. The salinity of your tank will be different than the LFS(or like many of us do, get them shipped from another area of the country) or wherever they came from. Also, the temp needs to be adjusted to reduced the opportunity for shock, especially after a day in a hot/cold, bumpy ride. More shock occurs due to sudden environmental changes than a slow process of making their conditions better. Although it is good to get them in better conditions, doing this too quickly has a much higher chance of shocking a fish/coral than deacclimating(I think I may have just made up a new word) them from improper conditions(such as a bag with higher waste, lower oxygen, etc). Although improper, they have still acclimated their body to it, osmoregulated to that SG, and since cold blooded have brought their temperature to that of the water in the bag. This needs to be taken care of slowly, but also with caution not to proceed to long. It all really comes down to how severe a variance is in the conditions from where it came and to where it will be placed.