Cost+ accounting for a contract means that the contract is awarded at face value, and the contractor is allowed to bill more than face value for a variety of re

Cost+ accounting for a contract means that the contract is awarded at face value, and the contractor is allowed to bill more than face value for a variety of reasons, mostly based on if the government changes/adds requirements (blows projection estimates up), moves locations (employee compensation changes), increases delivery needs, things like that. It also often ends up getting abused by the contractor who will claim "market forces" or something forced production costs to increase, or "unforeseeable complexities" lengthened production time (such as with all of the set backs in the joint strike fighter programs). What will be a real blow for Boeing is if they actually have to execute options on the "+" side of that -- if SpaceX hits their cost target and Boeing costs not only double, but triple, good luck wining the next contract as a prime.