The Dockstocker and the Pacer are similar units. There is a pass code needed to set the speeds which your dealer should have provided.
Travel and hydraulic speeds may be set to meet your specific needs.
With a Quad upright hydraulic speed may need to be raised. Travel speed should not be too high but when using in and out of a trailer has to be high enough to provide enough power to transition over the dock equipment being used.
As only you know your application, operator capabilities, and production needs it should be your decision but it will also be your liability should something happen. A safe and productive work environment is important while serving your customers needs.
I suggest discussing it with the folks who sold you the equipment.