Unless otherwise agreed to by the board of directors of a nonhigh school district, the amounts which are established as due by a nonhigh school district pursuant to RCW
28A.545.030 through
28A.545.110 and
84.52.0531, as now or hereafter amended, shall constitute the entire amount which is due by a nonhigh school district for the school year for the education of any and all students with or without disabilities residing in the nonhigh school district who attend a high school district pursuant to RCW
28A.225.210, and for the transportation of such students by a high school district.