MergableFiles contains a list of lists {Reason, threshold, value} and this will only match if the list has one element and that element is data_expired. This works but we could have some files who pass merge thresholds for fragmentation AND data_expired which will be put through the old merge process. It would be a nice improvement if those instances also went through the merge_expiry function as all the data is expired. It works in the current implementation but there are some cases(such as high update AND using data_expiry use case) that will not see the improvement implemented by this change.