Number Ranges in Organizational Management

i would like to suggest to my client to maintain number ranges with below series that contains 8 digits as below

Organizational Units - 20000000 - 29999999

Jobs - 30000000 - 39999999

Positions - 50000000 - 59999999

All number ranges maintained are IN. I didnt maintain EX.

Is that above is okay to go ahead? Could you please clarify