I've recently started using Pinap Berries from time to time and have experienced inconsistent results.
I've not yet used any on evolved Pokemon yet, but the Basic Pokemon I used them on gave me either 5 or 6 total candies. All of them have evolutions, though I didn't pay attention to whether the 5 and 6 were split between 1-stage and 2-stage evolutions.
So, how many (extra or total) candies does Pinap Berry grant, depending on which factors?