Different result between select, after applying SUM () and Grop By [closed]

I am making an elastix bind report and I have a problem here in the output. Theoretically, if I do not touch Where , the result would have to be the same.

select distinct
(case left( devices.id ,2)
when '10' then 'SAC'
when '40' then 'SAC'
when '41' then 'SAC'
when '80' then 'OUTROS'
when '70' then 'OUTROS'
when '90' then 'RECEPCAO'
when '91' then 'ADMINISTRATIVO'
when '92' then 'COMERCIAL'
when '93' then 'T.I.'
when '95' then 'SAC'
when '98' then 'PROJETOS'
when '99' then 'DIRETORIA DE T.I.'
else ' ' end) AS  grupo ,
round(sum(cdr.duration)/60)   AS  "duracao

from ((cdr  join  devices  on(( devices.dial  = substring_index(cdr.channel ,'-',1))))
join  trunks  on((substring_index(cdr.lastdata ,'/',2) = substring_index( trunks.channelid ,'/',2))))

where outcid = '12121212' and
!(left(cdr.dst,4) = 0800) and
(char_length(cdr.dst) > 4) and
cdr.duration > 60 and calldate >= '2014-02-01' and calldate <=  '2014-02-20'
group by grupo with rollup;