Nicanor,
I'd say that, in general, both drilled the same, relatively strong, given their nature and what they were designed to do, the Natural should cover light to medium-light oil and the Ogre Urethane should cover dry to light oil. A lot depends on the drilling and the bowler's release.
With your ball speed, you might never need a ball that requires as much dry as the OU. And you would probably be able to use the Natural with a string drilling such as 4x4 on light oil.
Maybe your driller didn't encounter enough dry for the OU or had ball speed similar to yours. Possibly he drilled it too weak. It does have a high RG (2.6) and a fairly low differential, .030, which results is low flare (2-3"). If he used, oh, say, a 5" pin to PAP, he'd get even less flare.
The Ogre Urethane IS supposed to be a hard shelled solid urethane in the 78 - 80 degree of hardness range. If he needed to sand it, there was probably too much oil or he has too much ball speed.
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"None are so blind as those who will not see."