I tend to run 35 all round in disco with standard tyres and 30 all round with my 33x12.5s.
there is far more weight potential in the rear so the tyres are recommended harder, also like you say the fronts are set at the lower limit for better traction, but it depends how you use/load your car. my weight is distributed more centrally than as the factory would have it, so my pressures are set accordingly.
i havent experienced poor traction ever so i tend to run higher pressures, not just in the land rover. used to run around 34 in the front and 38 in the rear of my track civic to reduce resistance and encourage oversteer. the front pressure could be noticed as the front end did all the work, the rear was a random number almost cos the rear just trundled behind basically.
one thing that track work taught me was that tyre pressures are up to you, not what the manufacturer says. the manufacturers recommendation is a start point and then you can decide what characteristics you want to increase or reduce by altering the pressures accordingly.
i run my tyres hard in the 4x4 because it has never made a noticeable difference to performance ON ROAD and the reduced rolling resistance (which can be seen in the sidewall bulge) is worth saving fuel on.
cheers