McGraw-Hill and Differentiated Instruction

I am loving the new Readers Writers Workshop and how it helps our teachers put the gradual release model into effect.  It is so much easier to say the RWW is for modeling, but once the students read the anthology or the paired reading it is solely group work and independent work.

But, what I am not loving is the differentiated instruction aspect of it.  Why?  Well, first of all it gives our teachers a false sense of what true differentiated instruction is.  Because a lot of our teachers think, "Well, the curriculum tells me to use these materials, then I must." To a certain extent we should use the materials from our curriculum, but what if those materials do not meet the needs of your students?  If you analyze the Lexile levels listed within the McGraw-Hill, you will find that the resources for the approaching level is ON grade level.  And those of us who assumed that we could use the ELL leveled resources for our lowest students have found that often times these books are even higher than the approaching and on level texts!  Take a look at one example from the 3rd grade resources:

We've started to address our differentiated instruction by pulling in other resources.  Does this frustrate your teachers?  What have you or will you do to ensure that your resources are aligned to each group's data?