Assesments for English Learners

In my classes I only have one official English Learner. She tested at an Early Advanced level according to her CELDT test. Due to the fact that teachers must teach at the L+1, I teacher at and advanced level when differentiating my lesson for my English Learner. I do see a fault in the CELDT system because it appears as though I have more than one student who are English Learners, but have somehow slipped through the cracks of the system. This is problematic because I have to evaluate them beyond the CELDT test on a day to day basis. The struggles of teachers.