First of all, there is the obvious difference of being able to move more than one object with the Move Multiple Objects command. The more subtle difference is that the Move Single Object command allows you to move one object in relation to all other objects in the sign, while the Move Multiple Objects command allows you to move a group of objects relative to another group of objects - excluding all other objects in the sign. This is a very important difference. With the use of the Move Multiple Objects command you can isolate two objects or two groups of objects to align.