number ranges from EXTERNAL to INTERNAL

Dear all,

I want to change the Customer Master number ranges from EXTERNAL to INTERNAL.

Is it possible (and recommended) to do so with the same number range?

I tried to do so and following are the observations:

1- It started from the very first number (and not from the last created)

2- Though it is creating in sequence but in OVZC it is showing a random jump (after 9309100005 the next showing is 9309100009 though the one created is 9309100006)

Please give your inputs.

Regards

SAPshed