Only 250 around calls are process from 1000 destinations

Steps to reproduce : 

1. Admin login
2. Customer edit
3. Set CC value = 0
4. Go to inbound -> voice broadcast -> create
5. Select .csv file 1000 destination
6. Click on save button
7. Wait until broadcast executed completely
8. Check total number of processed call into CDRs. 

Expected Result : remaining calls are hang-up with "SWITCH_CONGESTION" but entries not available in CDRs. Here customer CC value is 0 so all calls should be process successfully.