Product allocation in interactive demand planning

Dear APO Gurus:

I've faced a problem about product allocation in interactive demand planning. The scenario is like this:

1.We defined two levels for product allocation, say they are sales org and distribution channel. If we maintain product allocation qty as 1000pcs in the sales org level. And then if we maintain the product allocation qty as 2000pcs in distribution level. APO automatically update the qty in sales org level to

2000pcs.

2.So, are there any macros or effective ways to avoid this problem occurs? We don't want it update the upper level automatically? We hope it will restrict the distribution level not exceeding 1000pcs. How can we do that?

Thanks for your kindly advice,

Scott