'Line Up Time' is the length of time you've been synced with the exchange, and 'Online Time' is the time you've been connected to your ISP. So, although you haven't lost sync for 12 hours, something caused your PPP connection to be dropped about 3 hours ago. This can happen from time to time, and isn't anything to be concerned about unless it happens frequently.
None of this will affect your bRAS profile. You don't have to be in sync continuously for three days for the profile to update; all that's necessary is that any resyncs continue to be at a similar connection speed. To be specific, if you don't sync at less than 4544 kbps for three days, then your profile should go up to 4000.
Eric