Problem using xymonping in short time (xymon 4.3.7)

Hi,
i have configured the xymonnet to make  tcp and ping test every 1m,
timeout 2sec and retest every 20 sec.
This is my configuration file:

# "xymonnet" runs the xymonnet tool to perform the network based tests - i.e. http, smtp, ssh, dns and
# all of the various network protocols we need to test.
[xymonnet]
         ENVFILE /opt/hobbit/server/etc/xymonserver.cfg
         NEEDS xymond
         CMD xymonnet --report --ping --checkresponse --timeout=2
         LOGFILE $XYMONSERVERLOGS/xymonnet.log
         INTERVAL 1m

# "xymonnetagain" picks up the tests that the normal network test consider "failed", and re-does those
# tests more often. This enables Xymon to pick up a recovered network service faster than
# if it were tested only by the "xymonnet" task (which only runs every 5 minutes). So if you have
# servers with very high availability guarantees, running this task will make your availability
# reports look much better.
[xymonnetagain]
         ENVFILE /opt/hobbit/server/etc/xymonserver.cfg
         NEEDS xymond
         CMD $XYMONHOME/ext/xymonnet-again.sh
         LOGFILE $XYMONSERVERLOGS/xymonnetagain.log
         INTERVAL 10


The tests (for now i do only ping test) are corrected only for the first (i suppose) host.
The other hosts, one the response time is over 20ms, seem to maintain their "baseline" to 20ms.
First host:


Other host :


Any suggestions ?

Marco