With compression as low as the numbers your reading, you should definitely be able to hear air leaking in the crank case or intake/exhaust if you hook an air source up to each cylinder in turn. I performed the same test on mine before I tore it down. If I recall correctly the lowest cylinder had around 230 psi and I could definitely hear air through the oil fill. In this case, it correctly identified the rings as the culprit. This test doesn't take long, and is very informative.
BB

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