I always run 12-3 brutal in campaign farming for XP. (and silver).   I use level 60 Rae, and three "food" champs.   Before the forge pass, I used to have the Raid pass plus the 100% XP boost.   This resulted in over 10K xp each for my three food champs.   I have canceled the Raid pass some time ago.   

However, the new Forge pass came out, and I have level 3 which says +30% increase to XP and silver.   I also have the 100% XP boost active,.  However, I am getting less than 10K per food champ.   I know we now live in a weird world where 2 + 2 can equal 5 depending on feelings of the individual student, but in what's left of the real world, +30% should yield a greater amount of XP and silver than +20%..

To be fair.  I am not certain the silver calculation is also incorrect.  I don't remember what my silver intake wwas with only raid pass.   Currently with forge pass (+30%) I am getting a shade over 14K silver.

But the XP is definitely messed up.