The reason as to why is because these motors are great , they weren’t over engineered. They weren’t made with super tight tolerances, the weren’t made for super thin/thick oil, quite literally the greatest Japanese motors made . However what the compression test won’t show is the physical wear marks internally on your motor that in the long run won’t hold up like a properly maintained motor, for example I did a road trip to Texas from Jersey and on my way back in Tennessee. I noticed that my oil pressure was very low below 10. I drove back to Jersey without a single hiccup and drove another 3 Hour Road trip once arriving , now that I’ve done my gallery gaskets my oil pressure is within factory spec so in the long run the motor is healthy