Meaning of 'bytes' on dba_data_files - tablespace appears full but isn't

Hi all, I'm feeling slightly confused here:

I ran the following query on hearing that the customer was having trouble with VMS data:

select tablespace_name, file_name, bytes/(1024*1024) Mb, maxbytes/(1024*1024) "Max Mb", user_bytes/(1024*1024) "User Mb" from dba_data_files
where tablespace_name like '%VMS%';

VMS_INDEX \ORACLE\PRODUCT\10.2.0\ORADATA\CUTLAS2\DBF\VMS_INDEX1.DBF 1335 32767.984375 1334.9375
VMS_TABLE \ORACLE\PRODUCT\10.2.0\ORADATA\CUTLAS2\DBF\VMS_TABLE1.DBF 2500 2500 2499.9375

This made me think the VMS_TABLE tablespace was full. So I deleted about 60% of all the VMS data, then ran the following:

alter table vms_.... enable row movement;
alter table vms_.... shrink space