I disagree, too. I've always noticed that though the sounds at the end of sush words are very similiar they are not the same. I even remember a time when, context didn't show an adjective of what gender was said and relying on what I heard I made the right choice; and I don't think the speaker articulated intentionally.
I think if you will pronounce them the same, you won't be wrong. However, I advice you to do it the way natives do. Inspite of what is said in your coursebook, I hear different sounds pronouncing the words. By contrast I feel that my mouth is a bit more widely open while pronouncing вкусная and the positions of the toungue slighty differ.Could someone clarify this for me: do these two words sound the same and is the difference only in spelling, or is there a difference in pronunciation as well?
вкусная
вкусное