I have no idea what she's saying now about her time in Dreamgirls, but the fact is that she regularly blew out her voice and as a result missed literally dozens of performances both in New York and subsequently during the LA run (which ended up losing money because of her many absences). Her attendance record was awful and there were weeks when she couldn't do more than 2 or 3 performances of her scheduled 8, especially towards the end of the run. When I saw her at a Saturday matinee shortly before she left the Broadway production, her voice sounded patchy and almost painfully raw -- it was nevertheless an incredible performance -- and from what I heard she had missed the Friday night performance the night before and went onto miss the Saturday night performance that evening.
To be fair, every Effie who ever did the role missed performances -- it's simply too demanding to sing Effie in the manner that Holliday did 8 times a week, month after month. By the end of the Broadway run, Bennett had installed 4 separate understudies for the role because it wasn't unusual at any given time for the main Effie to be out and for one or two of the understudies to also blow out their voices trying to handle the role in replacement (I actually saw a third understudy -- a young Kecia Lewis who was 19 at the time, fresh out of HS for the Performing Arts -- one of the times I went back to see the show late in the run; everyone else was out on vocal rest).
Ideally, Effie should be treated the same way Evita is (as well as Marie Christine and the lead roles in the The Apple Tree) with a separate actress doing the role at matinees to give the main Effie a bit of relief.
"What a story........ everything but the bloodhounds snappin' at her rear end." -- Birdie
[http://margochanning.broadwayworld.com/]
"The Devil Be Hittin' Me" -- Whitney