15. Amounts payable to a school which is, as the result of the discontinuance of one or more maintained schools, either established or, pursuant to Chapter II of Part II of the 1998 Act, the subject of prescribed alterations, to reflect the extent to which a school which has been discontinued has spent more than or has not spent all of its budget share (within the meaning of the 1996 or the 1998 Act) in any financial year. Any such factor or criteria must provide that any amount deducted shall not exceed the amount which the school receives during the financial year as part of its budget share by virtue of being a new school.