Re: TA and the STD button, it very much depends on the aircraft model you are using as to whether STD sets the FS baro to 29.92. For the very complex payware aircraft (PMDG in particular) they have their own baro separate from the FS baro, and pressing STD resets their baro, rather than the FS baro (hence it's very easy to get the baro penalty in PMDG aircraft if you forget to *also* press B going through 18,000ft AMSL [Above Mean Sea Level] to reset the FS baro)
Furthermore, you need to set 29.92/Q before passing 18,000ft AMSL as far as the logger is concerned, both when on climb and on descent (so below 18,000ft AMSL on climb out, and above 18,000ft AMSL on descent) to keep FLv3 happy. The logger can be a good few hundred feet behind FS, so better to get these works out of the way a little early.
I'm sure this is something we'll be "fixing" in FLv4 (along with a number of other "unfair" penalties... the B738 is happy to climb at greater than 6,000ft/min for instance (depending on load), but that incurs the wrath of FLv3, and has annoyed me for forever...).