[Robert]

When a physical adept uses the new metamagic astral projection, the text states

• "All the usual rules for Astral Projection apply". That would mean that e.g. no physical spells are possible, for example "increase reflexes" spell is not possible.
• "all of an adept’s powers may apply to their astral self". That would mean that e.g. adept "improved reflexes" would work.

What is true?
If 2 is true, a projecting adept would be MUCH MUCH faster, than anything else on the astral plane, as he would start with astral initiative LOG+INT+2D6 and then add his 4D6 from the power. He will not get benefit of the +4 on Reaction, but still that gives him LOG+INT+6D6, including 7 minor actions. So he could spend 2 minor actions for dodge prior to his turn and still have 5 actions available then.

[Typhus]

If "all" = "all" that's a big boost.  I would personally rule that they don't stack, but that the highest one does apply.  I can see the argument for this aspect, but it's not one I'm a super big fan of.  That said, 6e has evolved what's possible with magic, and leans towards more permissive.

In my mind, whatever the logic is that is used, it should mimic whatever happens to an adept when they use the Matrix.  I'm not sure this interpretation does that.  Do adepts get ref boosts in VR mode too?  There used to be a hard line between "worlds".

If I was running it as a GM, I would rule the bonuses from physical abilities don't apply, but mental ones would.  I'm assuming here that "all" = "any that would reasonably affect astral stats" (which would disqualify Improved Reflexes since that's only the physical body). 

That's just my opinion based on prior editions.  I defer to the errata folks and other experts for 6e.

[Xenon]

It says "may".

There are several adept powers that are not (may not be) applicable to astral. Wall running, for example. Just like cyberjack only affect VR initiative (not Astral or AR/Meat) it also make sense (at least to me) that Improved Reflexes only affect AR/Meat (and not VR or Astral).

But then you have adept powers (such as killing hands and mystic armor etc) that "may apply" to both Meat and Astral.

Anyway, that's my two cents