Hi Masa,
Now the logic is clear, and looks like you want to restrict access for some number of time periods at the beginning of the year (based on CATEGORY version). I don't see the reason to allow input of QTY without revenue calculation.
You have 2 options:
1. Use work status to lock the appropriate number of months for each category to prevent unwanted input of QTY.
2. Use validation badi to check version property like starting month and comparing it with time member send. Will also prevent posting in the beginning of the year!
Also you can prevent sending data for the periods defined in category dimension property in the input form (using Excel validation rule method).
About DM to recalculate revenue if price changed - yes it's possible to calculate only on periods after some period/
B.R. Vadim