Plans loading in STS vs count in SPM doesn't match

Dear Team:-

I am in process of upgrading my critical production 90TB env to 12c from 11.1.

I am testing the SPM by loading the STS from awr  snaps to SPM but all the time the count doesn't match between the count of statement loaded into sts and count of baselines .

SQL> SELECT NAME,OWNER,CREATED,STATEMENT_COUNT FROM DBA_SQLSET where name='ST04';

NAME       OWNER                CREATED              STATEMENT_COUNT

---------- -------------------- -------------------- ---------------

ST04       W7131252             12-JUL-2018 09:02:02             528

[++ ]  After loading into SPM [  not using basic filter to remove the sys or sysman ,... ]

SQL> select count(*) from dba_sql_plan_baselines;

  COUNT(*)