Is there any reason why Changeling Dermal Alterations would not be compatible with worn armor? Is this a mistake in book?

I think it was intentional - the rules always seem to be against any kind of armor stacking...except for FFBA...and PPP...and other stuff...

no, it makes no sense, except from an attempt at game balance perspective

I think they figured it would upset the game balance. I think because it is bulky as armor it counts as armor. It should probably just use normal armor staking rules.

Only granite shell and rhino hide are incompatible with worn armor - they are only worth getting if your other SURGE traits would make wearing armor difficult (tails, extra arms, spikes, etc.). I'm assuming the limitation is there for game balance, since either quality gives you the equivalent of dermal sheathing or orthoskin, or maybe even slightly better.

It doesn't make sense, of course - someone with rhino hide could still wear a slightly oversized armor jacket. Why would that not make it even more difficult to damage the character? But then again, someone wearing an armor jacket over an armor vest is as easy to damage as someone wearing just the armor jacket. So I don't have a problem with treating it as non-stackable with armor - but I think they should still be able to use the higher of the two values when wearing armor. The restriction would make sense if the quality made the skin too inflexible to wear anything bulkier than normal clothing - but why the line about it counting for armor encumbrance, then, if it doesn't stack with other armor? All in all, not well thought out, and should probably be slightly tweaked by the GM to be more consistent with the other armor rules.

Because THE THING wears no armor.

Personally I house rule armor to stack. FFBA is just another type of armor. I wind up with a wide variety of outfits, which don't involve wearing thermal underwear. Your body is naturally going to limit the amount of armor, key is to stay away from options which increase the amount you can wear to maintain balance when using this option. The degree of difference between well chosen off the rack clothes and custom fit is a matter of appearance and to a degree fit, and while fit is important to your ability to do things while wearing armor it does not suddenly make it weigh less, and really weight is the primary factor.

was it one of the earlier editions that let you stack armor, but you only could stack "2 layers" and you only got like half of the value of one of the layers? getting old...can't remember...

I'd be ok with some kind of rule that let you stack armor, but with a diminishing gain from stacking, and maybe a resulting increasing penalty to Agi or Quick or something...

Definitely older editions. The way I look at it is that there is zero reason for the armor to be less effective if you layer. For simplicity we already have the 2xBody as a limit. Outside of the high Body tank it won't push armor totals past what they are with FFBA underoos. You might even want to limit it to two layers. Clothing and a vest, clothing and a jacket or lined coat, definitely not military armor with a lined coat, for lack of a hard and fast rule, common sense should prevail.

Thats just stupid, either let all armor stack or not, making up some wierd rules about diminishing returns pretty much removes the whole point of allowing armor to stack, that being more variety in characters clothing.

I think you need to go back and re-read your post, for multiple reasons. I hope you find them. Good luck!

If you have somthink to say then write it, instead of making snide cryptic comments.

As far as I can tell, the original point of not making armor stack was to ensure that you had to get the expensive(and obvious) full combat suits(and later milspec armor) to get a high armor score rather than just wearing multiple layers of concealable or mundane armor.

Later, PPP and FFBA were added. The PPP I have no real problem with. The PPP is bulky and as obvious as combat armor, so it carries most of the same disadvantages, and it doesn't let you break the armor 2xbody limit. FFBA I don't like, and I typically either outright ban it, or make it rare, expensive, and illegal. Not only is it not usually obvious, but it allows you to wear more armor than normally would be able to, and it's not terribly expensive for a runner either. There are no real disadvantages.

As for the SURGE qualities, the Granite shell is hardened armor, so it makes sense it doesn't stack, as it's two different kinds of armor score. Rhino Hide I can honestly find no good reason, be it for flavor or game balance that it doesn't stack with worn armor, as long is it still counts for encumbrance I say let it stack.

Just a small note, but PPP doesn't always have to be bulky and obvious...

"Each piece of armor is available in at least three styles: as discreet protection de-signed to be worn beneath other clothing, as an obvious strapped addition to other visible armor, and as sports equipment."

Also, it doesn't count towards the body limit for encumbrance purposes.

Having said that, I do agree with you that PPP isn't really a problem, for the most part.

Maybe from a game balance / design sense, not letting Granite shell stack makes sense. But from a slightly "real-world" perspective, I don't think it makes much sense. Real-world...SR..I know, I know

Umm, yes it does.
Would be pretty damm broken if it didn't.

TheOOB, my bad - I'm reading the line from Arsenal "These armor pieces do not count as separate armor for purposes of encumbrance; "

I think I've been blocking the "as separate armor" line from my memory and have been doing it wrong this whole time - so you're right there, PPP doesn't let you break the armor limit barrier