Note that Darkvision doesn't come into this the way you seem to think, and neither does Darkvision interact in any way with the fact that HiPS may be (Ex) or (Su).
Just weird to think about since the ability is using shadows not as a supernatural ability to your advantage to hide where someone with Darkvision at the correct range doesn't care about that. Like Shadowdancer is supernatual so they don't care.
"Shadow Blend (Su): In any conditions other than full daylight, a 7th-level Dark Moon Disciple can disappear into the shadows, gaining total concealment.
Artificial light does not negate this ability, though a daylight spell does.
This benefit replaces the wholeness of body class feature that the standard monk gains at 7th level."
"Shadow Blend (Su): In any conditions other than full daylight, a shadow creature can disappear into the shadows, giving it total concealment. Artificial illumination, even a light or continual flame spell, does not negate this ability, but a daylight spell will." I don't know if I use it if I'm always 100% concealed as long as I'm in the darkness or I need to activate it at some point with a free action perhaps?.
Unfortunately, I cannot XP Jimlock.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.