The answer is still the same, even if there was an avast5,ini parameter (which as far as I'm aware there isn't), the basic problem is still there and avast doesn't generally run an update immediately after coming out of sleep, that is down to the update interval. I have a win7 netbook which spends most of its time in sleep, I don't hibernate it as I don't like the hiberfil.sys file size that it creates to do this.
Now I have my update check interval set to 2 hours, so in most cases it will have been in sleep for more than that interval ,so is likely to check for update on coming out of sleep. Which it just has updating to VPS 130305-1.
That may well suit your needs better than this fast boot, as in doing a fast boot, you are also shutting down the OS and that effectively suspends that update check interval. On a normal boot avast would check for updates and the update interval would then start.
You could also reduce the update check interval further, I believe the Pro and AIS versions can go as low as 15 minutes.