Wrong "tom" I know, but I add the recommended dosage. I don't think you want excess nutrient left around after the yeast is done, especially free available nitrogen. This only provides a more hospitable environment for bacteria. This is something that is attended to closely by winemakers. I know the nutrient blend doesn't seem to have much DAP in it but I do believe it has some amino acids. Plus if theres zinc you might not want a lot of extra of that either.
I think its like taking two vitamins, maybe one thing in there is useful at an elevated concentration but theres other stuff that might be just the opposite. Since we know you can make good beer without the nutrient to begin with, I wouldn't go with a dose higher than recommended. They're selling the stuff after all, they have every reason to recommend a higher dose.