Subfolders getting deleted while using the file mask

We are using the below script for archiving the files.

E:\app\WinSCP\WinSCP.exe /console /command "option batch on" "option confirm off" "open sftp://user:server:port" "mget -delete -filemask=<60D /Source/ Destination\" "ëxit"

It's coping and deleting the files (older than 60 days) including files under sub folders to destination but it is deleting the Sub-folders as well if they are older than 60 days.

We just want only files to be removed after successful transmission not sub-folders.

Can someone please advise what needs to be done for that.

Thanks,

See https://winscp.net/eng/docs/library_example_moves_files_keeping_directory_structure