[hannes69]

I do need Reclock for PAL speed down though, so maybe I should just stop obsessing over this.

If you are already using Reclock and it is working for you without problems, yeah, you probably could stop obesessing over this
I haven´t used Reclock for a very long time, maybe it can be a source of problems too (like your wrong values of the clock deviation, maybe there is no real problem but rather a kind of cosmetic bug showing wrong values... just guessing)

Is the same audio clock of an HTPC used for all outputs, for example?

Hm good point. I don´t really know. I have a simple setup, I have a stereo professional soundcard and I use simple analog stereo outputs, nothing digital in the chain, no receiver and so on. There may be differences depending on the audio setup i guess.