Yes, that could well interfere with updating.
AVG has a problem with updating anyway and although it is wise to leave it set to auto check for updates it is adbvisable to MANUALLY check at least once a day--only takes a few seconds.
I am running the dreaded Windows ME system at work, but I think this question pertains to most Windows operating systems. I use AVG Anti-Virus and it is set up to automatically check for updates and automatically run a complete scan every 24 hrs. However, based on the logfile, it appears that it has only been running the test roughly every 10 days. If the machine goes into standby mode, will this prevent the scheduled anti-virus activity from taking place? That is all I could think of that might prevent the sceduled task from taking place. I have used PCs heavily since 1991, so I feel like a novice asking this question, but the answer has eluded me thus far.