Hi,
when I am trying to change in an old Sales Order a message appeared that a pricing error : Mandatory Condition is missing.
could you check in the condition records whether the Validity dates are maintained correctly or not ?
I guess your validity dates were maintained as in MWST for your new tax condition, just change them accordingly
Also I need the Tax Condition to be updated for the Sales Order created from the first day of the Month
in VA05N transaction you can update the Price for all the Sales order
or even in the va02 you can do price update for individual order if the volume is less
thanks
santosh