PReqs getting deleted and recreated in SNP

SNP Gurus,

I see some issues in our SNP run which is causing some serious concrns in our ECC community.

We run our SNP in Net Change mode. Even then we see evry single PReq getting deleted and 're-created' again, which basically consumes a number from number range for PReqs in ECC. This way we end up consuming miilions from the PReq number range. Should not the SNP run just change either the quantity or the date in the 'existing ' PReq insted of deleting every PReq and recreating them again? I have tried to find any other suitable setting but so far has been unable to see something. We are on SCM 702, SP 8.

Thanks,

Subash