I feel there is misconception on CEPs for Ballistics which aren't exactly circles so the term itself is a misnomer - They are elliptical in nature which means its greater along the flight path rather than lateral. So the 10m CEP is likely 50-100m at best on just GNSS and INS.
Now with the seeker onboard there is another aspect, you need to actually slow down for the seeker to achieve resolution from plasma blackout for a lock so being hypersonic consistently isn't always a requirement. With the seeker then the window for the missile to achieve a lock and then make adjustments to course starts to matter.
Against defended targets with electronic countermeasures, the effective CEP degrades significantly because jamming can deny the terminal seeker its target lock, forcing the missile to rely on increasingly inaccurate INS-only guidance.
HOWEVER, you don’t need every round to be a 10 m CEP hit if the operational objective is to achieve a mission kill, force defensive expenditures, or disrupt operations.