OH.
In that case ... both yes AND no.
I don't think your ECL should count towards your leadership score. Your actual class levels (and HD, if appropriate) should be all that counts there.
However, most Level-Adjusted races, even those down in the +1 range, should easily qualify for the "reputation of special power" by the time they can get Leadership. a Half-Celestial, after all, DEFINITELY has "special powers" ...
Heck, even an Aasimar or Tiefling does!
However, that +1 is ALL I'd give, for the entire ECL "package". Part and parcel of hte cost of playing a level-adjusted character (some of whom already get healthy Charisma bonusses anyway, which DOES add directly to Leadership score ...).
Now, the one place I'd let ECL factor in fully, is the cap for Cohort level/ECL. A Half-Celestial Sorceror(10) is ECL(13); IMO, a Human Cleric(12) is perfectly legitimate as a Cohort for our putative sorceror. Why not, 13th level is lower than (ECL) 13th level ... right?
And no, it's not impossible to get there. BEtween being a sorceror, levelling up a few times, and being Half-Celestial, it's not unreasonable to suspect such a character might have an innate +6 Charisma modifier. With a "reputation of special power" that's a +7 modifier, giving a raw Leadership score of 17.
The character, especially if it is a PC, may just have a "reputation of great prestige" by 13th ECL, and probably has a Cloak of Charisma +2 or +4 as well. So, we're up to 20 or 21.
Toss in the -2 for having a familiar ... and you have 18, enough for a 12th level cohort. Were this a human Sorceror(10), somehow with the same stats and items ... he'd be stuck with a 9th level cohort.
But it's not, it's a Half-Celestial, of ECL 13. So as a GM, I personally would allow the ECL to set the "Chort Level Cap", so a 12th level Cohort woudl be entirely appropriate.
None of this, AFAIK, is official, however. It's just strongly IMO.
But I think it tends to make SENSE, as well as beign FAIR. 8) YMMV, of course.