Audio, CC, EPG data is allocated as part of the transport stream and don't use the "extra" space afforded by lower FEC. Picture quality is only one factor when a satellite broadcaster selects a FEC. A link budget determining the delivery requirements of a service is created while arranging for the lease or usage of bandwidth on a satellite. Together, the signal type, power, FEC and bandwidth selection determines the robustness and quality of the service. This calculation determines the parameters required to deliver the complete transport stream (that encapsulates the video, audio, cc, epg, etc.) within a specific region using minimium equipment requirements with an expected up-time.
If the link budget is for the downlink facilities which have small aperture dishes, located near the edge of a footprint or where conditions affect reception, then a lower FEC might be selected. This lower FEC is not as efficient by using the least amount of bandwidth to deliver the same data, but it would allow smaller dishes or in regions with inclement weather conditions to receive enough data and have more data duplication to mask the errors that are caused from not receiving all of the data on the first pass.
Downlinks with larger dishes, located in prime footprints and minimal signal attenuation receive more data without errors and do not require the extra duplication of data to mask and correct errors. For these link budgets, a higher FEC might be used so either less bandwidth is used (lower cost) or the same bandwidth is used to provide increased picture, audio or data streams.