The directory name reflects the day when the bloom filter was received. It seems that it took your node around two days to process the bloom filter.
Whether it took your node few seconds, or 5 days to process the bloom filter, the Storj network starts counting time in which it believes trash can be recovered from the time the bloom filter was sent to the node.
By marking the date of collection, as opposed to date of removal, you can flexibly change the trash expiration period after garbage collection—which is a good idea in case something really bad happened to the network.