nate,
I teach at a charter school in Oregon and was involved in the process. How does Oregon City get away with giving you guys only 75%?? Charter schools ARE public schools and the school district receives the same level of state funding for charter school students as it does for all other students. The state sends districts monies based (for the most part) on ADM, which is basically your average daily attendance calculated over a year.
BTW, state law requires more than 75%: The following is from the Oregon School Boards Association website.
"If a school district is the sponsor, it must contract with the charter school to pay for educational services. The payment must equal an amount per weighted average daily membership (ADMw) that is at least equal to:
80 percent of the amount of the school district’s General Purpose Grant per ADMw for students in grades K-8; and
95 percent of the amount of the school district’s General Purpose Grant per ADMw for students in grades 9-12."