I did some testing myself.
Regular heroics require 180 ilvl, that is correct.
But for some reason ToC, Forge and Pit normal require 210, even though ToC only drops 200.
I reckon Halls of Reflection requires 219 on normal as my 212 character can't sign for it on either normal or HC, but can sign for everything else.
It makes no sense that ToC normal requires 210 on average, when it drops 200.
Same thing goes for Halls of Reflection normal, which drops 219, requiring more gear than signing for Forge and Pit Heroic, which both drop 232 and require 210 to sign for.
Again, I don't know if it was like this on retail. But at least I got my question answered.