Leak Down Test Results Diagnosis

I’ve performed a leak down test on a Honda D17 engine. I’m getting a leakage rate of approximately 30 percent on all cylinders. The leakage seems to be mainly from the exhaust valves. I’m planning on lapping the valves, but before I do I would like to know if this is a sign of something else other than damaged exhaust valve seats? I haven’t done many leak down tests, and looking on the internet I haven’t come across any diagnosis of high leakage rates across all cylinders. Would this be a sign of bent exhaust valves? Is there a way to determine if the valves are bent?

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