The initial perks for the Block tree affect a value called 'Mod Percent Blocked' by multiplying it. Is there a way to read this value from a ReferenceAlias script that targets the player? I already know about GetAV and went through the list of available actor values, but there doesn't seem to be one that corresponds to this.

I've found the actor values BlockMod and BlockPowerMod, which correspond to block bonuses provided by enchantments and alchemy, respectively. However, neither of these seems to be affected by changes in the blocking perks, so I'm still unsure of to get the 'Mod Percent Blocked'.

I suppose in the worst case scenario, I could just check the player's perks directly and do my own math to get the block bonus from perks, but then it won't match up if the player has mods that change/add blocking perks, so I'd really prefer to figure out a way to access 'Mod Percent Blocked'.

SKSE may be able to help? http://www.creationkit.com/GetNthEntryValue_-_Perkthis function might work, but it probably only works if you know exactly what you're looking for. I don't believe there is an easy way to access a value for this perk functionality.