partition range (empty) partition:invalid

SQL> Select count(*) from cy_work where work_id = '10316'; --### why no records returned?
 
  COUNT(*)
----------
         0

SQL> Select count(*) from cy_work where work_id = 10316; --### records returned number value
 
  COUNT(*)
----------
     78121

Table partitioned by range on WORK_ID, data type varchar2(5)

Some of partition definitions:
PARTITION PM005_WORK VALUES LESS THAN ('08947')
PARTITION PM006_WORK VALUES LESS THAN ('10484')
PARTITION PM007_WORK VALUES LESS THAN ('13674')

Data was meant to be in partition PM006_WORK which has a top value of 10483 higher that 10316
But data is located in partition PM007_WORK....Why is this so?