The honey section says that “Anything above 3EPA or so will be a better honey grind than any actual honey grind.”, but this seems very wrong to me. Let's calculate. Send him out for a little more honey gives 125 drops, which will cost 5 Echos if buying from Bazaar.

Send him on another errand is more profitable, but not 150 H/A as stated in the article, since it's impossible to achieve a 100% success chance. The highest possible chance is 96% with fate-locked items and 93% without them. If Lead Evensong is used for reducing scandal, it is ~135 H/A with using fate-locked equipment and ~125 without them. If my calculations are correct, you need at least 5.4 EPA grind for buying honey to be better than any grind. Also, you need fate items for Send him on another errand to be better.