Change the value posted in CE1XXXX table

Hi,

We had a customer#1000 in sales order while first settlement has been executed and customer#1000 has been updated in table CE1XXXX with record type A. Now user changed customer on sales order to 2000 and all new settlements are going with customer number2000.All this is fine.But now the user is asking that even old customer values in CE1XXXX has to be changed to 2000 in place of posted values 1000.

Is this possible if so is it riskY or advisable?

thanks hinfi