Shadow Form confusion - Basic question.

So I read GWPvX builds for sin runners/solo farmers quite a bit, some with attached movies. They say things like "keep Shadow Form up 100%" or the likes. Then I watch movies, and these people have Shadow Form buff icon up 100% of the time.

But then I head over to paw-end^2 or wiki and it states Shadow Form lasts ~20 seconds, with a recharge of 30 seconds. What is going on here? I even went through the Wiki history of Shadow Form and it says nothing about it ever lasting longer than that, nor did it have a shorter recharge.

Also, the builds are not using any "extends x by y%" abilities.

Enchantments last 20% longer weapon mod and Deadly Paradox makes assassin skills recharge 33% faster. Alternatively, in older days, Arcane Echo and Glyph of Swiftness were used.

Also if you are watching youtube videos of sc's(speedclears, such as Fissue of woe, Underworld, DoA, Dungeons) The probably are using an Essence of celerity,which shortens the recharge of all skills.

Ahh that's what it is, completely slipped my mind.

Serpent's Quickness with Dwarven Stability, and to a lesser extent Quickening Zyphyr, are also options for perma-Shadow Form maintenance.