How can Netsuite prevent changes to transactions in the past?

Hi there

We mostly use inventory/purchasing/sales/CRM and have a basic accounting structure to support our transactions but we haven’t fully integrated our accounting into Netsuite. We still have that in a separate system, our CFO did not want to take all the risk at once, we are looking to migrate accounting this year.

We have a stumbling block before we can get there. We have an issue with the ability to create a transaction in the past that affect months that are ‘closed’  I say closed, but there seems to be nothing preventing me from changing a transaction that was done in November 2007 for example, and have it ripple though and change all of our inventory numbers. This has happened accidentally recently and has every one in accounting freaked out.