Issues with Two sets of a load balancer subordinate's web server. (no replies)

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.