It isn't a set number of 1% at each school, but an average. If you have 25 kids who qualify and I mean truly qualify all they need to do is fill out the paperwork.
Yes, they can read the whole passage as well as the questions and choices. From the PARCC website:
After the reader finishes reading a test item and all response options, the reader must allow the student to pause before responding. If the pause has been lengthy, say: “Do you want me to read the question or any part of it again?” When rereading questions, readers must avoid emphasis on words not bolded, italicized, or capitalized.
When reading passages, readers must be aware of punctuation marks. Readers may read the passage, or selected lines a second time, with all punctuation marks indicated.
When test items refer to a particular line, or lines, of a passage, reread the lines before reading the question and answer choices. For example, the reader should say, “Question X refers to the following lines…,” then read the lines to the student, followed by question X and the response options.
http://www.parcconline.org/sites/parcc/files/appendix-b-ta-protocol-human-reader-1-15.pdf
Just to add more on math specifically for students who need accommodations:
The student uses a calculation device (e.g., four-function calculator, large key or other adapted calculator), arithmetic table (including addition/subtraction and/or multiplication/division charts) and/ or manipulatives (IEP or 504 plan must specify which device or manipulative) on the non-calculator session of the Mathematics test.
What more do you want them to do if they do not qualify for a separate test? This is an abundance of options. Using manipulations, charts and calculators are a huge help and can often be enough to even the playing field with the addition of extra time, not to mention all the options with a reader.