MH370's New Search Area Far From Aircraft Fueled Range

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"The new priority area is still focused on the seventh arc, where the aircraft last communicated with satellite. We are now shifting our attention to an area further south along the arc," Australian Deputy Prime Minister Warren Truss told reporters in Canberra.

We, professional pilots, can have this logical reasoning:

There wouldn’t be the seventh ping if there weren't the six previous pings, so researchers cannot force us to accept their calculations for the flight mileage totaling 4700 nautical miles, where they assume that the wreckage of the plane could be found.

Once the aircraft took off from Kuala Lumpur direct to waypoint IGARI, and it deflected westward (VAMPI waypoint), and from there it had its navigation to the first ping, and after this point it took heading to the South until it reaches the new search area on the seventh arc, thus totaling 4700 nautical miles of flight, but the plane was fueled for not flying  beyond 3200 nautical miles.

Why do they insist on searching the aircraft black boxes 1500 NM far from the plane fuel range?

We can think either the seven pings are INMARSAT false signals or the searchers have hidden crucial information about MH370 true flight path.