1. A computer program product for reconciling billing measures to cost factors, the computer program product comprising: one or more computer-readable data storage devices and computer executable program code stored on at least one of the one or more computer-readable data storage devices, where the computer executable program code when executed on one or more processors causes the one or more processors to provide an adjustable tenant billing to cost mechanism as a platform service from a platform-as-a-service (PaaS) layer within a distributed multi-tenant computing environment that comprises multiple distinct host computing platforms, comprising causing the one or more processors to: receive, at the PaaS layer over at least one application feed from at least one software-as-a-service (SaaS) application operating in a SaaS layer within the distributed multi-tenant computing environment, a set of client-application billing measures of multi-tenant computing services; receive, at the PaaS layer over at least one infrastructure feed from at least one multi-tenant platform host operating in an infrastructure-as-a-service (IaaS) layer within the distributed multi-tenant computing environment, a set of service-provider cost factors of a plurality of different types of platform and infrastructure components used to provide services within the multi-tenant computing environment; analyze the set of client-application billing measures and the set of service- provider cost factors using a set of defined relationships within the PaaS layer that identify influence of the set of client-application billing measures in the SaaS layer on the set of service-provider cost factors in the IaaS layer; and adjust, in accordance with the analysis as an improvement of the platform service provided from the PaaS layer and using a feedback mechanism within the multi-tenant computing environment, the set of defined relationships within the PaaS layer that identify the influence of the set of client-application billing measures in the SaaS layer on the set of service-provider cost factors in the IaaS layer.