(B) an active or retired school corporation or charter school employee shall pay for the coverage provided to the active or retired school corporation or charter school employee under this section an amount that is at least equal to the amount paid by an active or retired state employee for coverage provided to the active or retired state employee under the state employee health plan. However, this subdivision does not apply to contractual commitments made by a school corporation to individuals who retire before July 1, 2010, or by a charter school to individuals who retire before July 1, 2011.