It's often difficult to know, with a hybrid ICE, just how much the engine really ran as a % of the total miles of the UOA. Certainly, the 20k miles of vehicle use didn't result in 20k miles of engine run time; that's a given.
Even if we assumed the engine ran 50% of the distance (10k miles), it's still not a bad average for Fe, and the other wear metals are low enough to be considered noise.
This is more proof that the TBN/TAN topic is overblown. The TBN being "low" (per BS), as well as not knowing the TAN, didn't affect wear adversely whatsoever.
Si, when the source is an intake tract leak, should be progressive in a fairly linear state. You don't have any other UOA data shown so we can't really understand how bad this may or may not be. Given the universal average of 17ppm @ 8.4k miles, your reported value doesn't seem all that "high" given that you went 2.5x further than the "average" distance.
Next time, perhaps take a UOA every 5k miles to see how the trends develop. Yes - it's expensive. But having more data points helps understand the condition of the oil as it matures, rather than just having a single snapshot in time.
