about the output of "fix ave/correlate"

Hi everyone,
I used the "fix ave/correlate" command to compute the stress
auto-correlation function and output it to a file. I have got the SACF
as expected, but at the end of the output file, there are extra lines I
don't know what they mean.
The "fix" I used is like this:
"fix 2 all ave/correlate 1 1000 1000 c_2[4] type auto ave running start
10000 file pxyacf.data overwrite"

And at the end of the "pxyacf.data" file are as follow. I wonder what
are the lines after the "1000 999 989002 -3.61065e-06" mean, it seems
that they are not explained in the manual.

987 986 989015 -3.4047e-06
988 987 989014 -3.4315e-06
989 988 989013 -3.45648e-06
990 989 989012 -3.47963e-06
991 990 989011 -3.50094e-06
992 991 989010 -3.52041e-06
993 992 989009 -3.53804e-06
994 993 989008 -3.55384e-06
995 994 989007 -3.5678e-06
996 995 989006 -3.57995e-06
997 996 989005 -3.59028e-06
998 997 989004 -3.59883e-06
999 998 989003 -3.60562e-06
1000 999 989002 -3.61065e-06
2 -3.70159e-06
7116e-06
e-06
2 -3.82457e-06

1000 999 696002 -4.56885e-06
7565e-06
9 694002 -4.55914e-06
07
7
1000 999 493002 -3.06721e-07

65039e-07
7
53488e-07
817e-06
53002 -1.21691e-06
51002 -1.5151e-06
00 999 450002 -1.79345e-06
15e-06
6
999 170002 -1.6618e-05
5

1000 999 151002 -1.94155e-05
1.58962e-05

Thanks in advance.

I'm having a bit of trouble reaching the sandia.gov site at the moment to check exactly what the manual says, but that looks to me like it could be a consequence overwriting an existing file.

Does it work correctly if you delete the existing pxyacf.dat before starting?