LEED Healthcare EQc2 - Acoustic Environment

We are working on a small clinic, and were considering pursuing EQc2, Acoustic Environment from LEED HC as an innovation credit. We found that the project will be required to achieve an STC rating of 50 to meet the credit requirements. However, we also found that we could only meet a STC rating of 50 through the use of a proprietary assembly, which we cannot use on federally funded projects. Instead, through the use of non-proprietary assemblies, which we can use on federal projects, we can only meet a STC rating of 49, unless we add an additional layer of gyp board to make "generic" assemblies compliant. Not only does this add significant costs to the project, but it also increases the amount of material, waste and labor generated in the building's construction - all for very little additional acoustic value. This doesn't seem to be the best approach by LEED for the credit, considering projects are using BMP's to meet the credit's intent (and are really at an almost equivalent acoustic rating), but are limited as to whether the assembly used is propietary or non-propietary. Does anyone have any insight as to why this might be the case? Would LEED be open to us pursing this as an innovation credit, considering we really are meeting the credit's intent?