Lightning conduit +1 corruption level skill window

Noticed lightning conduits damage skill window doesn't show that it gains damage from +1 level corruption.
When you hover over the skill gem lvl 20 it states "Deals 101 to 304 Lightning damage"
And when you hover over the lvl 21 gem it states "Deals 114 to 342 Lightning damage"

But the dps window says that both have 6836 dps and both have an average damage per use of 9365.

Image of them both slotted without any support gems
https://gyazo.com/1e1c3db5aab20218f105bb3b7e84e4de

Images of them slotted into cast on shock
lvl 20 https://gyazo.com/5880018fb4cb47426fba9a63c34e472a
lvl 21 https://gyazo.com/2d19279855522b215619726d023993d2