Both the Marxist and the will to power notions of truth are flawed, for basically the same reason. Marxist (Hegelian) view of truth proposes that truths are assimilated together in synthesis, that differences become opposites and meet somewhere in the middle; will to power claims that one truth overpowers another and assimilates it into itself.
Both ideas are stupid.
Luckily Nietzsche actually advocated a third view of truth, the Revaluation of Values. This is more than simply a thing meant for moral values or mere conceptions, it applies to truth itself. Parodites has more fully explicated this in his own Daemonics, and so has Fixed with his VO.
The real view of the nature of truth is as follows:
-Separate truths exist
-Separate truths can interact with one another
-Separate truths can reinforce or complete with one another
-A new truth can appears which explains and comprehensively encompasses other separate truths. This generates a third point, a meta-truth. I believe this is close to what Parodites calls the epistemes.
There exists a hierarchy of all truths, which is the fact of how truths work together and stack up derivatively around and through one another, without infringing upon or cancelling each other's existence either by will to power domination or by synthetic averaging. My view of Tectonics is precisely this, the hierarchy of all truths functioning together in tectonic planes both horizontally and vertically.
The task is to become more comprehensive over time, thus elevating oneself further up in the hierarchy of truths, creating more vantage for oneself. The scientific, analytic, positivist, postmodernist, or will to power sort of approaches are actually holding oneself back to a specific tectonic plane, in which it can be the case that certain truths can be examined in relation to each other according to power dynamics or synthesis. Synthesis or domination are then misread as an obliterating of those truths which are said to have been synthesized or overcome by domination.
In reality, no truth is ever abolished. A synthesis or domination occurs when a third term is formed, a meta-truth over the different truths in proximity to one another; the third term is a higher truth that encompasses and further explain the lower truths without cancelling or falsifying them, but under Marxist and naive Nietzschean reading this is glossed over or ignored entirely. Thus most people and most philosophers remain stuck at very low tectonic thresholds.