Yea, if you put quality at 100%, it will make HQs until it runs out of mats or around 30 crafts. I never quite figured out why it would stop after 30-40, but its still way faster than using the crafting bot.
when you use WPE it will craft and give you the item until you run out of the current stack of material that the craft is pulling items from, after that you gotta restart the craft and use WPE again.
Note : the same is true of result items.
Eg: If you fill a stack in your inventory, it will stop producing.
Reaching x99 in Silver Ingots for instance, will require you to stop and restart the WPE Crafting.
That could be what Ive seen. It seems like its usually around 33, so a multiple of that would make sense.