We propose to have OT because of loading/unloading. Machine is equipped with legs for truck transport. Loading/unloading with crane or fork lift truck. With HC we use different kind of legs and with these we can push/draw machines in/out container.
When machine is equipped with truck transportation legs and you want to use HC, you need to have rolls and jack to load/unload machine in/out container. Not so easy and will take a lot of extra time. And if you use HC, there is big risk to break something during loading/unloading.