Average is determined by salvaging an item and comparing it to the TP sell price (including 15% tax for items pre-salvaged/post-salvaged). All items are assumed as drops/in your inventory already.
Unidentified Gear Profit Choice
General rule of thumb for unidentified gear:
All unidentified gear is assuming you open then salvage. For more data on direct vs non-direct salvaging, check Wiki (listed at the bottom).
- Blue → Copper-Fed > Basic Kit
- Green → Runecrafter's > Copper-Fed > Basic Kit
- Yellows → Silver-Fed or Mystic Salvage Kit > Master's Salvage Kit

Note: Outside of unidentified gear, the list above is the order of salvaging kits if you don't happen to have some such as Runecrafter's.

As of 7/21, you can sort by Item or Choice, but not the rest yet.
Item Copper-Fed Runecrafter's Silver-Fed Choice