Unilateral and Reciprocal Cover Eligibility 
The component incorporates the functions with which you can make additional budget available if you require more on the expenditure side. These additional expenditures are then covered by smaller expenditures in other functional areas.
Unilateral and reciprocal cover eligibility can only be used if the following conditions are fulfilled:
Budget Structure functions must be used and budget objects must be defined in the budget structure.
Active availability control must check against years based on the valid budget profile.
The commitment type profile function which controls the Behavior of Availability Control for Commitment Postings must not be activated.
If you have defined in the update profile that the active availability control must check against releases, the released budget is automatically eligible for cover.
This restriction does not apply for German Government customers.
You should be aware that only a limited number of elements that are eligible for cover are checked. For more information on this, see Unilateral and Reciprocal Cover Eligibility .
You have to differentiate between two types of cover eligibility:
Unilateral cover eligibility
With unilateral cover eligibility, an expenditures FM account assignment (A) may use the still-available funds eligible for cover from (B) to cover its additional expenditures, but not vice versa; B may not use funds from A. A is entitled to cover, B is subject to cover.
Reciprocal cover eligibility (cover pool)
With reciprocal cover eligibility, an expenditures FM account assignment (A) may use the still-available funds eligible for cover from (B) to cover its additional expenditures, and vice versa; B may also use funds from A. A and B are mutually entitled to cover and subject to cover.
Several FM account assignments mutually eligible for cover are grouped together in a Cover Pool .
A set of rules to be created in master data maintenance describes general account assignment-specific relationships between FM expenditure account assignments. These rules form the basis for the active availability control (AAC) checks. If the budget for the expenditures account assignment is not sufficient, the AAC checks if this expenditures account assignment is authorized to claim budget from another FM account assignment. AVC does not take the tolerance limits defined in Customizing into account. The budget from another FM account assignment is used if the budget is used up (usage level 100%).
For both unilateral and reciprocal cover eligibility, you can decide per FM account assignment if you want to use it in the payment budget and/or the commitment budget. The point at which "external" budget is claimed is determined by the business transaction (e.g. funds commitment, invoice, payment) which generates assigned values on account of the valid Update Profile .