Scott Foresman Science: What's wrong with this picture?

In the near future, I will be meeting with the science team at one of the schools I work with to help them with incorporating content literacy for ELLs, especially newcomers and those at the lower levels of proficiency.

Our district uses Scott Foresman Science textbooks. The one pictured below is the 2nd grade edition.

As part of my preparation, I wanted to put together a few tools and strategies they could use- among them, offering simplified texts. On a whim, I decided to test the readability of the text. SHUT. THE. DOOR. I could not believe the results.

On average, out of 5 sections that I tested in the 5th grade science book, the average readability on the Flesch-Kincaid scale was 7.4! On the Lexile™ scale, the average readability was 920 (which is the upper readability expectation for 6th grade).

I then decided to check out 2nd grade. Again, I tested 5 sections. The average readability on the Flesch-Kincaid scale was 5.5. On the Lexile™ scale, the average readability was 780- close to the upper readability expectation for 4th grade.

While this is not exactly a scientific study with a large sample, it certainly does raise concerns. How can our students possibly be successful with acquiring content when it's presented at a reading level two grade levels above where they're expected to be- IF they're on grade level?? (You and I both know it is almost never the case that an entire class is reading on their expected grade level- frequently many will be below grade level- even several grade levels below). What about our ELLs and SpED students who struggle even with texts that ARE on grade level for them?

I did email Pearson to inquire about why the readability of these textbooks is two grade levels above that of the students it's written for, but I doubt I'll get a response.