Reducing maxDurationSeconds on existing videos

We had a large 60 minutes value set to maxDurationSeconds for Direct Upload links and it seems on average our users do not upload more than 2 minutes videos. It has occupied the storage space given each video is claiming 60 minutes. Using CF API, I tried to reduce the maxDurationSeconds to actual duration of already uploaded videos in order to empty some storage space but the API call does not make any changes and maxDurationSeconds property remains unchanged. Can anyone advise?