It's like a compression test but it gives you a percentage of combustion leakage on each cylinder. And a clue as to where it's leaking from. True I wouldn't think it's likely to be blowing by the rings at 93k. But possibly through the valve seats, depending on if you had them re-cut and lapped, and how good the worksmanship was. I often see 'proffessionally built' classic Porsche engines with less than 20,000 miles on them leaking past valve seats due to shoddy work.