What is the differences between the contractors and consultant-quantity- surveyor?

A contractor quantity surveyor is professional who practice quantity surveying profession for the safe guardness and the benefit of a contracting firm in which some of his responsibility will be to submit tender documents for the and also to supervise and take proper measurement of every job done by the company while a consultant quantity surveyor helps his client to get proper value for his money in executing and project, he gives cost advice to the client atv the prelimnary stage ogf construction and he still makes sure the standard of workmanship, plant and functionality is still maintained..... though both are only aiming toward same primary goal which is to provide value for the person they are representing and at the same time still optimize production and qualitative standard of job done.....