It is perfect if the results of top-down and bottom-up figures match.In general however, The resulting sales, profit etc differ.
In order to resolve the issue, the basic assumptions of top-down budget has to be detailed down so as to match bottom-up figures.
Otherwise, the budget is a top-down-order which the employees will not “own”.
Of course, the resulting budget figures in any case should satisfy financially the top-down guys : upper management, board and shareholders.