for the big shop: definetely agreed upon
to give it some dimension, my rough stats from yesterday's 8h session in the bookshop (with roughly 20 minutes per hour taking a break, so ~2h 40m net restock time):
items bought: ~450
np spent: ~310k (~690/item)
estimated profit: ~1.3m (~425%) (~3k/item)
note that I have rather high buy times (~5s on average), so I missed most of the more valuable items (mostly those with >30k profit), so with faster buy times you could definetely do a lot better.
You bought 450 items in 8 hours?