New York state education regulations as written and implemented throw stumbling blocks in the paths of students with IEP/504 Plans. In New York state a student with an IEP/504 Plan that includes an extended time testing accommodation can end up enduring 12 hours of testing to complete Regents exams if they have two exams scheduled on the same day. New York doesn't reschedule these exams to accommodate students with IEP/504 Plans. One option is for the student to take one of the exams months later during one of the other allowed testing period in January, June, and August. The other option is to not take one of the exams at all.
The New York State Education Department will, on a case by case basis, allow schools to petition the state for permission to administer a test over multiple consecutive days to a student with this accommodation in their IEP/504 Plan. The petition has to be made months in advance of the scheduled exam and the state still has the option to turn down the request. Parents have to know this option is available to their students and school staff also have to be aware.
The regulations in question are here. Are accessible to families, students, or school staff? No. I'm not sure how you would find them if you didn't already know where to look and what to look for. Are they clear as to their purpose and how they can be implemented? No.
If this seems like an undue burden to place on students with IEP/504 Plans you are not mistaken. It is unclear how many students in New York state have their educational careers sabotaged by ambiguous and inflexible state regulations. What is clear is that these regulations need to give way to the precedents established by IDEA (download a copy if you don't have one) guaranteeing students with disabilities free access to an education. Right now students in New York state with IEP/504 Plan do not have that free access. That must change.