diff --git a/bsip-0040.md b/bsip-0040.md
index 47e030d..7e738d4 100644
--- a/bsip-0040.md
+++ b/bsip-0040.md
@@ -171,9 +171,13 @@ Adding a custom active authority means increased effort for the backend, and wit
 - `install_custom_active_authority`: Normal accounts can only create custom active authoritites with a duration of maximum 1 year, LTM can do any duration. Two options come to mind:
   - A fixed high fee independent of authorities content
   - Tied to the duration and complexity of the custom active authority. Transaction fee is then `fee = flat_fee + basic_fee * duration` where `basic_fee` is calculated according to complexity (e.g. size of authority, number of restrictions and etc.). Fee is capped at 1 year for LTM.
-- `update_custom_active_authority`: Base fee similar to `account_update` plus dynamic one for any duration changes
+- `update_custom_active_authority`: Base fee similar to `account_update` plus dynamic one for any duration changes, no payback if duration in decreased.
 - `delete_custom_active_authority`: Cheap similar to `limit_order_cancel`
 
+This logic forces the user to think about the desired duration and enforces to put it rather too short than too long. 
+If a custom active is expired, or considered to be too short, extending it is easily doable. 
+After expired, the custom active becomes disabled and can still be enabled again with a new period, paying the fee for that new period.
+
 ### Modification to the backend
 
 * Add a new index or extend the account object to store custom active permission are assigned to an account and contain a list of custom active authorities. Multiple custom active authority entries are possible for one operation