I trust dawg a lot, and that is what I would go by for personal use, but when it comes to selling eggs I would feel more comfortable having a vet advise a withdrawal.
Try searching for egg or meat withdrawal times for praziquantel. If you have a vet, have them contact FARAD for a recommendation on withdrawal times.
http://www.farad.org/
Maybe they should say something like "in my opinion the meat/eggs" should never be eaten, because there is nothing from the FDA or the AVAMA that backs up this claim.
If I understand it correctly, just because something isn't "labeled" or "approved" does not mean that the drugs will render the animal not usable for food, milk, or eggs. For example, if your pig, cow, or goat needs to be treated for tapeworms, your vet can prescribe praziquantel and then it is...
Two reasons... The injectable is not water soluble, or at least mine isn't, and the injectable does not contain praziquantel, and praziquantel is needed for tapeworms.
But for regular lice and some mites, injectable ivermectin is what I use.
One thing I forgot to mention is that the medications in Zimectrin Gold are not approved for use in laying hens so most people will advise an egg withdrawal. There is a vet on a Facebook group that recommends an 8 week egg withdrawal for ivermectin.
In the future, you might want to consider...
I don't know... Metabolism could be part of it, might also be that poultry tapeworms are more difficult to treat than equine tapes. The cat tapeworm dose is more than the horse dose too.