Try that, for the previous #CallCost table

select aGroup, sum(datediff(ss, '00:00:00', aTime)) totalSecs,

sum(datediff(ss, '00:00:00', aTime)) / 3600 as hrs,

(sum(datediff(ss, '00:00:00', aTime)) / 60) % 60 as mins, -- %...