Here would be one possible way. This is with DFSORT, so let us know if you have "syntax" problems by pasting your full sysout in the Code tags.
You can "rationalise" the column numbers to minimise space used.
//SUMRECS EXEC PGM=SORT
//SYSOUT DD SYSOUT=*
//SORTOUT DD SYSOUT=*
//SYSIN DD *
INREC IFTHEN=(WHEN=INIT,
OVERLAY=(25:13C'0',40:13C'0',
55:13C'0',70:13C'0')),
IFTHEN=(WHEN=(6,1,CH,EQ,C'1'),
OVERLAY=(25:7,13,SFF,TO=ZD,LENGTH=13)),
IFTHEN=(WHEN=(6,1,CH,EQ,C'2'),
OVERLAY=(40:7,13,SFF,TO=ZD,LENGTH=13)),
IFTHEN=(WHEN=(6,1,CH,EQ,C'3'),
OVERLAY=(55:7,13,SFF,TO=ZD,LENGTH=13)),
IFTHEN=(WHEN=(6,1,CH,EQ,C'4'),
OVERLAY=(70:7,13,SFF,TO=ZD,LENGTH=13))
SORT FIELDS=(1,5,CH,A)
SUM FIELDS=(25,13,ZD,40,13,ZD,55,13,ZD,70,13,ZD)
OUTREC BUILD=(1,5,
25,13,ZD,M18,LENGTH=13,
40,13,ZD,M18,LENGTH=13,
55,13,ZD,M18,LENGTH=13,
70,13,ZD,M18,LENGTH=13)
//SORTIN DD *
121021 000079751.79
121014 000440494.52
121024-000241189.45
121321 000154520.73
121322 000002643.39
121323-000000000.06
121324-000227258.71
121424 000094288.24