[@AlphaLemming]

Originally Posted by ZOS_ChipHilseberg Correct me if I'm wrong, but can you compute the full duration and the start time and then multiply by 10% if the account has ESO Plus using an API for that?

This is the next point, there is no function to get the Premium Membership of a player without this workaround sirinsidiator speak of and checking buffs of a player seems not to be a 100% save way and certainly not the fastest.

Thats a wish, a function which checks for membership and calculates the given value with 10% and return it. There are not only the research times affected, XP got also a bonus i believe.

-- a simple example
function GetPremiumValue(integer value)
  if IsPremiumMember() then return value * 0.1 end
  return 0
end

With such a value i can calculate even positive or negative.