[MrBasse]

Have you tried dropping two totes before lifting the full stack? It seems like your robot is low enough that you could shave a few seconds off by dropping the first tote in and centering it, then dropping another on top of the first, and then picking up the two. It would keep your human player from waiting while your lift cycles. It might only be a few seconds here and there, but it could be enough to finish that third stack.