hi enduro
trade pricing rates get generated from new build construction, then they get transfered to the domestic market when people go from site to joe public.
a quantity surveyor is the cost analyser on a site. its their job to breakdown the costs of the materials and the labour based on averages/inflation etc at that particular time.
As a plasterer myself, i never charge per meter on domestic because there are too many restrictions. ie furniture, carpets, unforseen obstacles, customers who say one thing and then dont do it when you arrive lol!!!! tiling is slightly different as areas dont tend to get retricted as easily, so meterage is easier to conform to.
what i will say is meterage prices are a good way of generating a fair structure. the reason i say this is, take for example, dave, or sir ramic or any other pro tiler on here . they can do more meterage than the average newbe, so therefore they will produce more quality tiling in a day than a newbee/intermediate so therefore they will quite rightly earn more. but some people decide that they are worth more than they produce so they ask for a large day rate when in effect they aint worth it!! (this is commonly known as delusion lol) so pricing per meter when the situation allows it, is more profitable than day rate if you are good at your job (good meaning, quality, knowledgeable, experienced and quick) then you will deservedly earn big money, if you not then you take longer and earn less per day when averaged out.
so all in all, a quantity surveyor denotes the current prices and meterage sorts out the wheat from the chaff
hope this helps
ed