I know from experience that it's not needed. I also know from personal experience that I was getting better growth when I was spot feeding...
Now it comes down to "What did you spot feed your Zs and Ps?
I like to do a large mix of foods.
San Fransisco Bay Brand foods that I use in my mix.
Spirulina Brine Shrimp
Omega 1 Flake Food with Garlic
This is not a daily thing, I would only spot feed once or twice a week.