Budget amount is reduced after published the budget to the manager bellow

Summary

Budget amount is reduced after published the budget to the manager bellow

Content

Hi,

when using budget pool in compensation plan,

if a manager want to make some changes in his distributed amounts, 

after publishing the budget to the manager's bellow him, the original available amount is reduced, and if the manager want to keep a buffered amount not distributed this buffer amount is disappeared.

please look on the screen shot attached bellow for an example

 

is it how it should be?

am i doing something wrong?

is there no option to keep some amount undistributed?