How is extra damage done by explosive weapon calculated?

The bonus explosive damage is added as a proportion of the base damage in an AoE. For example, Torgue assault rifles add 150% of the weapons base damage as AoE damage, while Maliwan pistols add 135% of their base damage as AoE elemental damage (I believe Maliwan Sniper rifles add around 75%) on every shot. This AoE damage is not multiplied by critical it modifiers but is affected by gun damage modifiers (as it alters the base damage before the AoE damage is calculated). I don't know the proportion for Torgue pistols or shotguns, however, or if the Maliwan effects alter elemental chance (as I have seen them cause double elemental dot with one bullet, but I don't know if that was a fluke or not).