Thanks in advance for any help on this, our GM and I have been trying to find clarification on this for a week and I have searched all of the 40K forums and still didn't find what we needed.
The rules we have for AoW/Ros are to roll a number of d10 and subtract that amount from incoming damage. Is that still the correct rule or was this updated to be more like fields in RT/DW where you need to roll under a number in order to avoid damage all together? If this has been updated, can you tell us where? Our GM thought he had read somewhere that it had indeed changed, but we couldn't find it and therefor couldn't figure out what the appropriate numbers should be to roll under etc. Any help/direction would be much appreciated as a few of our party just gained access to these items (One Tech-Priest has AoW and our religious characters (priests,sisters of battle) got Rosriuses. We currently have IH as the main rules for them, but like I said RT (and I think Assencion) handles it way different and with every game getting errated EXCEPT DH anymore we're not sure what the deal is.
I did find this quote from June 2011 that was interesting, but it didn't really answer what we needed.
Well, today I got a reply from Mac Martin:
Salutations Acolyte!
Indeed the Rosarius is rare. This comes with a few caveats, however. It is a holy item, while plentiful within the Ecclesiarchy (and therefore not as difficult to acquire) it would be near-heresy for a non-Ecclesiarch / Inquisitor to carry one! It is always on, and it's power source does last 24/7, although only those without faith in the God-Emperor would wear it all the time.
So yes, mechanically it is "just better" but there are a lot of social implications that come along with a Rosarius. I hope this helps!