(Big Problem) too few messages generated multiple groups

When i send a sms to multiple groups for example #Group1, #Groupp2, #Group3
the amount of messages that are generated are too less.
Sometimes it generates 103 Messages, sometimes 130, then 123 but it should be ca.190 messages.

I use SMSTools as Gateway/SMSC.
When I look in playsms log i can see something like this:

“L2 sendsmsd # start processing queue_code:b60c6532acc83f14fd0c2cabee66fc8b chunk:0 queue_count:123”

SMSTools sends all messages generated by playsms without prolbems.
I think it is a PlaySMS problem.
I also inspected phonebook but all seems to be ok.

Please can someone help me. It is very importatnt because we use PlaySMS in our comnpany.

Duplicate or invalid group entries maybe? If do you send twice consecutively, it wil have diferent number of sms?

Thank you for your reply. I do not have duplicate phonebook or group entries. The only thing I found out, that if i export phonebook as csv i have a few phonebook memebers who have empty entries in the group cell for example
group1, goup2," " . I deleted the emty entries and reimported but it is the same problem. If i send consecutively it has exact the same amount of sms created.