Quick Update ...
By happen chance, we discovered yet another great math website a few weeks ago and we have been using it faithfully ever since.
Moby Math < http://www.mobymath.com > allows each student to work at his/her own pace and level. The initial diagnostic testing provides a starting point for each student and then the rate of progress is determine by the rate of standard mastery. Since starting we have now completed 711 standards, completed 767 lessons, and answered 52,867 problems. I also received a high level of support from parents during our recent conferences and am enjoying watching kids enjoy math once again.
I would also like to mention the developers have been very helpful and extremely responsive to thoughts and ideas for improvement.