Have to agree Andy, I cann't think of any petrol engine which produces less power at its rated speed than it does at max torque. It has to be said that the O-200 is pretty 'peaky' given that there is only 250 rpm between 75% and 100% power (according to the specification sheets). Which leads to a lot of the discussion in the US of the superiority of the C90 over the O-200.
When I read the article I presumed they had made a mistake with the second figure - although even they speculate there may have been an equipment problem. But cooling on a pusher installation is never easy - especially on a test stand, you only have to look at the recommended size of scoop necessary fro statically testing a tractor propeller installation (opening has about the same area as the top of the engine!!!
I'm more inclined to believe the type certificate than this 'testing'.