I have been looking also into this and have been asking myself these same questions. I've been doing the math on the schools and the housing allowance and I am not really seeing it.
I also have 3 kids, ages 12, 9, and 4. Looked into the same schools you did, my preference is ASD since it holds a similar curriculum to the school they are attending now, but the QR amount given for this is way short of the actual cost at ASD or similar schools.
As my numbers are right now the pay difference between my present job and going to QR will be spent in schools and housing, hence there is no point in actually taking the job, mathematically speaking.
Am I wrong? I've been doing all my research online and contacting the schools directly, and I am leaning now towards not taking the DEC position. Maybe you gents that are already there can shed some light on this.
Thanks.