sounds like their food options are 10 times better then what they probably would get in the wild.
I don't know if this diet is on any "approved" list.
If your looking for cheaper then instant hpw. We did up some ohpw using the original wamboroo power. (the diet our two new girls are on.) At $50 for a 1 kg box, that would make up 16 containers of replacement nectar, plus the cost of raw honey. Its definitely cheaper then instant.