Custom Serial Number Sequence Lost

Hi,

We are creating custom serial number using hook USER_PKG_SERIAL.generate_serial_number. Everything is working fine except when two user as same time release jobs.

For ex. Job1 has quantity 5 and Job2 has quantity 3.

Desired serial numbers should be created for Job1 are SER001,SER002,SER003,SER004,SER005 and for Job2 are SER006,SER007,SER008.

But in reality serials are created like Job1-> SER001,SER002,SER004,SER006,SER007 and Job2->SER003,SER005,SER008

This is happening when two WIP jobs are released at same time.

Is there any way to achieve serial numbers in sequence for a job?