My guess is that for a lot of processes, crematoria included, capacity is not some fixed number below which everything is fine and above which the backlog piles up.

It's like my parents' restaurant, you can get busier and busier without there being a wall. When you "hit capacity" you find you're doing many things that you weren't normally doing, like being open a lot longer, asking for longer shifts from staff, rationing things that you wouldn't normally ration.