The addon isn't taking the Netherlight Crucible's +5 ilvl per relic into account. This is causing SIL:GearSum() to return totalScore as 30 points (5 ilvl * 3 relics * 2 hands) lower than expected before being divided by the totalItems count which results in the average ilvl being reported 1.9 ilvl lower (for a fully equipped character with the Netherlight Crucible unlocked and first trait taken for each relic). This can be hotfixed for fully equipped characters by adding totalScore = totalScore + 30 at line 676 of SimpleILvel.lua but this will then over-report low level characters without the crucible unlocked. A proper fix should be added to this function which inspects the relics' Netherlight Crucible status.