Issues with Two sets of a load balancer subordinate's web server

Hi.

We are using piwik version 1.10.1.
We have two sets of a load balancer subordinate’s web server(linux apache).
About each log, although import_logs.py is used, there are the following problems.

・When read continuously, the number of visits will increase steadily.
・Whenever it performs, the numbers of visits differ.

We use
python2.7 /home/apache/htdocs/piwik/misc/log-analytics/import_logs.py
–url=http://192.168.1.1/piwik/
–idsite=1
–recorders=6
/tmp/site1/access_log20130311
/tmp/site2/access_log20130311

・Are directions for use enough?
・At what kind of time is the “–add-sites-new-hosts” option used?
・When erasing the log of only the day or overwriting, what should we do?

any help appreciated, please advice.