No it wouldn't: material exchange has always counted towards the weekly caps. So the conversion would have gone more like this: 1000 materials --> 100 marks, 500 rep 100 marks --> 200 materials, 0 rep 200 materials --> 0 marks, 100 rep 0 marks --> 0 materials, 0 rep IOW you can get a 20% rep bonus at the cost of throwing all your marks away.