I am not certain that there is a "limit" to the amount of higher ordered thinking that one can feature in the design and execution of lessons. I think that much of this depends on several variables that will determine how much higher ordered thought is featured in lesson design. The first is the overall comfort of the teacher. I believe that the best higher ordered tiered instruction and learning happens when the teacher is comfortable with the material and comfortable with being able to perch out on the branch where there is much in way of student inquiry and exploration. Teachers need to develop comfort with this and understand that it might be acceptable to develop tasks and assignments where students generate the thought and products that reflected higher ordered thinking. Additionally, teachers have to engage in enough instruction with the rudimentary elements so that students can have some frame of reference with which to place these ideas into a higher ordered context. It does not help students to approach higher ordered thinking tasks if they lack the basic instruction. Students cannot progress with higher ordered tasks on fractions and number theory if they lack understanding on what a fraction is and how it is represented. It is here where teachers must focus their attention, setting up lower level thinking skills in higher ordered contexts.