Three systems, three funding stories
Network: caller to PSAP (ESInet / NGCS / CAMA) — separate contracts. CPE: what the telecommunicator uses — Fixed Allotment + residual. Location: GIS / ALI / MSAG — usually a different pot.
Changing one does not fund the other. Cutovers still have to be coordinated so 9-1-1 does not drop.