'MAKI' is not four digits, it's four characters...
If certain numbers are already used by one number range then, naturally, they can't be used by another number range. This would defeat the purpose of having a number range. Vendor number is the key field in database, so it has to be unique. If certain combination of characters is allocated to one number range and you somehow "trick" the system into using it under another number range then how would this work on the database level? Wouldn't this cause some issues when the number range that is the legitimate owner of the number in question reaches the number that was "stolen" by another number range?
I'm just curious - how did you envision the result of such design?