Common Sense... The manufacturer instructions should be followed. They designed the machine to be operated in a given application. For example, rough terrain forklift manufacturers train operators to carry loads as low as possible on "low boom mount" telehandlers... the same manufacturer will say carry loads high enough for the operator to look underneath the boom so they can see in the forward direction and see the mirror mounted on the front of the truck to be able to check the right side clearance on "high boom mount" trucks. Container handlers carrying containers need to drive in the forward direction in yards many times to make sure they have clearance on both sides... it is much harder to do that driving backwards. This is not a warehouse lift truck carrying a 48" pallet. So it is safer for many concerns in some applications to drive with a elevated load for better vision in the forward direction. Most container handlers carry loads in the elevated position, just high enough to see. If the yard is designed for plenty of clearance... nothing wrong with driving in reverse with load lowered, but it will demand more open yard space. Some container handlers have elevated cabs for better operator visibility... that may change the manufacturer's instructions on load carrying height! The design of the machine and its application must always be considered. OSHA 1910.178 laws are written for most applications. OSHA officers understand if a machine is designed differently or the application is not "the norm" the manufacturer may alter the normal forklift operator instructions. That's why we have interpretation of OSHA laws. Does the OSHA CFR1910.178 have laws dealing with how to properly clamp a roll of paper with a Cascade attachment?