Difference in clients Antivirus Corporate 10.1

I've tried contacting Symantec tech support but after two weeks and two levels of support they seem unable to be able to tell me how their product works. I'm hoping someone here might be able to.

The issue I've found was the # of clients listed in the Symantec System Console (SSC) was different compared to the # of clients I had in Altiris Deployment Solution.

This was explained to me by Symantec tech support as after X days (default is 30) of a client not checking in with the SSC the record was deleted from the database. If the client checked back in the record would be re-created. So the about 150 computer's that weren't appearing in the SSC were because they were offline for too long. The problem was when I ran the computer status report for the previous month (which would include records from last week and last 24hr reports), which according to Symantec tech support reads from the same database as the SSC would produce a report with approximatley 150 of the missing computers.

first question why does the Reporting Server produce different records then the SSC since the SSC delete's these records?

2nd question is I've noticed days where I can find a computer online in Altiris and I can remote to it, but it doesn't appear in the SSC sometimes. In one case two computer's in one branch office were online, but not in the SSC. The next time I checked two days later they appeared. This has happened with offline computer as well

Eventually I want to move to End Point, but if I'm going to have this same problem then I'm not really in a rush to do that.

Information about my config
only 1 parent server running Corporate Antivirus version 10.2
Client's are windows xp sp3 running either version 10.1.4 or 10.1.7