With Ocado I select a time slot and they know what will be available with very few substitutions. Definitely not apples-for-pears level. It's up to them to tun

With Ocado I select a time slot and they know what will be available with very few substitutions. Definitely not apples-for-pears level. It's up to them to tune. They could make it exact(don't overpromise any stock) but then be stuck with unsold stock due to customers amending their orders. Or they can oversell slightly and offer refunds or returns for unwanted substitutions, which is what they do.