Change existing backup to do Automatic Cleanup

I am trying to get Acronis 2015 to actually do an automatic cleanup, but it won't do it. I want to keep 10 chains only. I do some manual backups to create some chains to try to get it to delete the old ones, but it just makes b2_s4_v1_2 versions for example, not b2_s5. Does it have to be an automatic scheduled backup for it to work? The target disk is getting full, and I want to clean up the old backup. The backup I want it to delete is the old full backup and the 10 incremental chains after that. Build 6525.