SQL nested select sum returns wrong integer - mysql

Question

I have the following select statement:
SELECT
T.name,
C.name as competence_name,
THC.competence_level_id as requiredLevel,
(SELECT SUM(UHC.competence_level_id) FROM user_has_competence UHC INNER JOIN user U ON U.id = UHC.user_id WHERE competence_id = C.id AND U.title_id = T.id GROUP BY T.id) as current_level,
(SELECT
ROUND(SUM(UHC.competence_level_id)/ COUNT(UHC.user_id))
FROM
user_has_competence UHC
JOIN user U ON U.id = UHC.user_id
WHERE
competence_id = C.id
AND U.title_id = T.id GROUP BY T.id) - THC.competence_level_id as gap,
C.id
FROM
title_has_competence THC
JOIN
title T ON T.id = THC.title_id
JOIN
competence C ON C.id = THC.competence_id
This returns the following result:
'Head of IT', 'Office', '7', '16', '1', '524'
'Head of IT', 'Empatisk', '2', '5', '1', '527'
'Head of IT', 'Målrettet', '5', '12', '1', '529'
'Head of IT', 'Udadvendt', '10', NULL, NULL, '525'
'Webudvikler', 'Office', '2', '3', '1', '524'
'Webudvikler', 'Outlook', '3', '4', '1', '526'
'Webudvikler', 'Målrettet', '6', '10', '4', '529'
'Webudvikler', 'Back-end', '9', '9', '0', '534'
'Webudvikler', 'Infosoft', '10', '5', '-5', '532'
However the result is invalid:
In the first row you will see the current level sum is = 16 this should be 9 (6 + 3)
The gap is also incorrect as the gap should be 9 / 2 = 4.5 - 7 = -2.5
So my question is what am i doing wrong? why is my SUM() function returning way to much.
Also note that the COUNT() returns the right value = 2
The Tables
title_has_competence
id title_id competence_id competence_level_id
'82', '165', '527', '2'
'85', '166', '524', '2'
'86', '166', '526', '3'
'83', '165', '529', '5'
'87', '166', '529', '6'
'81', '165', '524', '7'
'88', '166', '534', '9'
'84', '165', '525', '10'
'89', '166', '532', '10'
User_has_competence
user_id, competence_id, competence_level_id, progression
'1', '524', '6', '0'
'1', '527', '4', '0'
'1', '529', '3', '0'
'2', '524', '10', '0'
'2', '527', '1', '0'
'2', '529', '9', '0'
'3', '524', '3', '0'
'3', '526', '4', '0'
'3', '529', '10', '0'
'3', '532', '5', '0'
'3', '534', '9', '0'
title
id, name organization_id
'165', 'Head of IT', '1'
'166', 'Webudvikler', '1'
User
id, username, password, title_id,
1 ** , ** , 165
2 ** , ** , 165
3 ** , ** , 166