The S-IVB also ongoing to thrust at a lower level by venting gaseous hydrogen, to help keep propellants settled in their tanks and stop gaseous cavities from forming in propellant feed strains. This venting also taken care of Harmless pressures as liquid hydrogen boiled off inside the gasoline tank. https://lowpowersemiconductors53186.spintheblog.com/34314960/the-best-side-of-apollo-mcu