I have observed the same behaviour in my LDW-811s, i.e. I have scanned the very same discs 1st day, 2nd day, etc to detect ‘drift’ of Pi/Po values (1000 versus 600, for example). I scan them with same LDW-811s and with other Liteon (combo SOHC-5232K), able to report Pi/Po values despite the fact is not a DVD-RW. The combo is stable, i.e, 1st day, 2nd day, etc show similar scans, maybw 15% peak difference, at most.
But the 811s shows 60% differences and more (Pi & Po). So, it’s clear that the changing/irregular unit is the Liteon DVD-writer.
I have almost ‘gave up’ with these Liteon DVD writers, regarding them as flaw-awarded models (811s, 812s, etc), regarding all I have seen and read of user experiences. I continue studying the so-called ‘learning behaviour’ only by curiosity. The most practical decision is to buy another model (e.g. NEC).
The Liteon models have been designed to ‘learn’ (to ‘write’ anf ‘read’) upon each burning, but the user behavior is so varying (e.g., wide range of media, firmware updates forth and back, omnipatching write strategies, changing PC environment, etc) that I would admire the Liteon progrmmers if they could foresee all those possible scenarios when designing the algorithms of Liteon self-learning.
The case is the Liteys some times deviates themselves from the route (LEARNING BADLY) so it’s ‘normal’ you observe those Kprobe deviations. On the other side, there may be hardware control (temperature/voltage enabled) servo-control not very adjusted in these Liteys not very well designed, leading to a frequent mal-functioning).
There is more to be said, … questions?