Settlement rule amount exceeding budgetted amount

Dear all,

We have following scenario for our Client sytems.

Level 1 WBS are used for orgnization.

Level 2 WBS are used for planning & budgetting.

It will have structure as A0**-GX-**.

Level 3 WBS are used for actual postings.

It will have structure as A0**GX**.

Now under CJ03, when user selects level 2 WBS and then click on settlement rule, can he be allowed to input amount which is more than budgetted amount for this WBS.

If yes,what is the setting we have to do? If no, please tell me why user can not be allowed to do this?

Any pointers on this will be highly appreciated.

Thanks

Tushar Vhora