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John - fast scopes ?!? The 32mm maybe but the 60mm is only suitable for f/10 or longer focal ratios - and that means SCT, mak or refractors; not newtonians. And 60mm suggests big scopes - 50cm or more.
Very very few eyepieces are flat field - for good reason - most scopes aren't either. Being Japanese it's 10:1 they'd have designed to match the field curvature of such scopes which is opposite to that of newtonians.
Hence I'm not surprised at all to hear someone say half the field was not in focus - I'd bet they tried it in a Newtonian. Even a modest plossl would perform better.
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