SubExpireTime is probably not a Motorola feature. Perhaps you were not receiving the EMMs (Entitlement Management Messages) for whatever reason. Check your OOB (Out of band) S/N and lock. If it is becoming unlocked or has a really low Eb/No, that could be something that is possibly caused in your coax setup. Things like damaged cable, too much attenuation or use of low quality splitters could be a cause of poor OOB performance.