Incorrect data_size in QSYS2.SYSTABLESTAT

I'm running the following statement to get data sizes for all objects in a particular library on the IBMi (V7R4):

SELECT s.TABLE_SCHEMA, s.TABLE_NAME, t.SYSTEM_TABLE_NAME,s.DATA_SIZE DataSizeBytes, (s.data_size / (1024.0 * 1024.0 * 1024.0)) DataSizeGB
FROM qsys2.SYSTABLESTAT s INNER JOIN QSYS2.SYSTABLES t ON t.TABLE_SCHEMA =s.TABLE_SCHEMA AND t.TABLE_NAME =s.TABLE_NAME
WHERE s.TABLE_SCHEMA ='MYLIB' ORDER BY s.DATA_SIZE DESC

When I look at a particular table it says it is 1.8GB, when I look at that same object here:

\\IBMi\ROOT\QSYS.LIB\MYLIB.LIB\CXRWSPROCS.FILE<file://IBMi/ROOT/QSYS.LIB/MYLIB.LIB/CXRWSPROCS.FILE>

It shows as 35.2 GB.

FYI, "MYLIB" is just an example library name.

I'm trying to understand why they are so drastically different when viewing the file member from windows explorer and browsing to the IFS where the data resides to what SYSTABLESTAT contains.

Is there some procedure that has to be run to ensure that SYSTABLESTAT is periodically updated with the latest table metrics?

Thanks!

Matt