Inconsistency between sys.innodb_buffer_stats_by_table and information_schema.innodb_buffer_page

SELECT IF(LOCATE('.', ibp.table_name) = 0, 'InnoDB System', REPLACE(SUBSTRING_INDEX(ibp.table_name, '.', 1), '`', '')) AS object_schema,

       REPLACE(SUBSTRING_INDEX(ibp.table_name, '.', -1), '`', '') AS object_name,

       format_bytes(SUM(IF(ibp.compressed_size = 0, 16384, compressed_size))) AS allocated,

       format_bytes(SUM(ibp.data_size)) AS data,

       COUNT(ibp.page_number) AS pages,

       COUNT(IF(ibp.is_hashed = 'YES', 1, NULL)) AS pages_hashed,

       COUNT(IF(ibp.is_old = 'YES', 1, NULL)) AS pages_old,

       ROUND(SUM(ibp.number_records)/COUNT(DISTINCT ibp.index_name)) AS rows_cached 

  FROM information_schema.innodb_buffer_page ibp 

 WHERE table_name IS NOT NULL

 GROUP BY object_schema, object_name

 ORDER BY SUM(IF(ibp.compressed_size = 0, 16384, compressed_size)) DESC;

SELECT IS_OLD, if(`IS_OLD` = 'YES',1,NULL) AS `pages_old` FROM `INNODB_BUFFER_PAGE`;