Connection time is differently between fping and xymonping

Hello.

I attempted to use xymonping instead of fping. A part of xymonserver.cfg:

#FPING="/usr/sbin/fping"           # Path and options for the ping program.
FPING="/usr/lib/xymon/xymonping"   # Path and options for the ping program.

A strange behavior was found: connection time of xymonping is very big.

172.30.1.2 is alive (0.64 ms)   - this is fping
172.30.1.2 is alive (40 ms)     - this is xymonping

But it is only on web page and in rrd (graph in attachment). 
Connection time is same when command line of xymon host (Linux)
is used:

$ /usr/sbin/fping -Ae 172.30.1.2
172.30.1.2 is alive (0.63 ms)

$ /usr/lib/xymon/xymonping 172.30.1.2
172.30.1.2 is alive (0.70 ms)

Any ideas ?

-- 
Regards,
Sergey