an extra 100 or 200 kilos ain't gonna make a difference in burn on short round trip sectors. Fuel has to be pumped into the tanks sooner or later. It’s not as if it’s going to be wasted. The Fuel burn and savings is going to be the same whether you take min fuel or extra an extra 200 kilos.
Unfortunately that is simply not true, the latest figures our airline pushed out are that a 100kg of extra fuel carried on every flight costs us $390,000 a year. There are now literally millions of dollars a year to be saved in a big airline by reducing the fuel carried on every sector and it's little surprise that pilots are being pressured, directly or rather more subtly, to carry less excess fuel. As one of our Chief Pilot put it, "for all airlines, the days of carrying extra fuel because it makes us feel comfortable are over". I have to say I agree completely with that statement, if you have a decent flight planning system then sector fuel is going to be enough for most flights on most days.