Problems with setting throughput

Hi,
 I am running Kannel on Solaris 9 with the settings as given below. The throughput parameter is set to 1 and I am pushing messages at a constant rate of 3 msg/sec using the http interface; when messages are being pushed, the throughput setting does not seem to work as the messages arrive at the smsc at nearly the same rate. I have noticed that sometimes(once in 10-12 secs) the rate dips to 1 or 2 msg/sec but most of the times it is constant at 3. 

  After shutting down the message-generating script, Kannel keeps sending messages which are left in the queue,but now it sends at 1 msg/sec until the queue is empty.

  I have tried different settings for the throughput parameter but the result is the same - the throughput parameter doesn't seem to work if messages are coming in.  

  Is this related to queue size for incoming messages? Can anybody please advice how to solve this problem.


# SMSC CONNECTIONS

group = smsc
smsc = smpp
smsc-id = kannel
host = 97.253.98.33
port = 8000
transceiver-mode = 1
receive-port = 0
smsc-username = "BULK2"
smsc-password = "KLUB2"
system-type = "CMT"
service-type = "CMT"
address-range = ""
source-addr-ton = 1
source-addr-npi = 1
dest-addr-ton = 1
dest-addr-npi = 1
throughput = 1

# SMSBOX SETUP

group = smsbox
bearerbox-host = localhost
sendsms-port = 2222
global-sender = 2222
sendsms-chars = "0123456789 +-"
log-file = "/RAPapps/test/smsbox.log"
log-level = 0
access-log = "/RAPapps/test/access.log"
access-log-clean = true

# SEND-SMS USERS

group = sendsms-user
username = tester
password = foobar
max-messages = 3
concatenation = false