People are thinking, that the most important question by purchasing a used camera is the shutter count.
I don’t agree this, because You can never be sure, if the camera was water damaged or not, or was dropped from three meters or not – and don’t forget, a well equipped service can even reset the shutter count.
But people want to get something believable – so they use for example the EOSinfo software from the astrojargon.net.
I repaired today a relative old 40d, and i made a reading with the EOSinfo, and one with the SPT software. Here are the results:
I think, there is nothing more to explain. the EOSinfo gives You only the shutter count – so if the body was services at an official servicepoint, you will see only the actuations of the new shutter.
By the way, in this 40d I had to disassemble the phase sensor from the shutter cocking unit, as it was shorted by tiny piece of metal. After 212000 actuations it was full with a black powder, resulting from the weard of the mechanism.