Disclosed is a computer-implemented method and system to perform a travel-related Availability Computation. The method includes, at an Inventory System, initiating an Availability Computation by retrieving information relevant to a received availability computation inquiry; determining that portion of a travel solution that corresponds to a reference carrier and a context to be prorated; making a call to a Proration Service and providing the Proration Service with applicable context information; receiving from the Proration Service proration information comprised of a calculated adjusted Yield or a calculated adjustment factor to be applied to the Yield, the Proration Service using proration data that is maintained by a Revenue Accounting System to make the calculation; and completing the Availability Computation using the adjusted Yield or the adjustment factor to be applied to the Yield.