This excerpt taken from the FNET 8-K filed Sep 4, 2008.
Replacement. Subject to Tenant's indemnification of Landlord as set forth in Paragraph 8.7 below, and without relieving Tenant of liability resulting from Tenant's failure to exercise and perform good maintenance practices, if an item described in Paragraph 7.1(b) cannot be repaired other than at a cost which is in excess of 50% of the cost of replacing such item, then such item shall be replaced by Landlord, and the cost thereof shall be prorated between the Parties and Tenant shall only be obligated to pay, each month during the remainder of the term of this Lease, on the date on which Base Rent is due, an amount equal to the product of multiplying the cost of such replacement by a fraction, the numerator of which is one, and the denominator of which is 144 (ie. 1/144th of the cost per month). Tenant shall pay interest on the unamortized balance at a rate that is commercially reasonable in the judgment of Landlord's accountants. Tenant may, however, prepay its obligation at any time.