RPM packaging and the J value

In the tests that I tried for the J value(value to change cpu setting) have not really had any big differences, where the fastest elapsed time for a build clocked in at 2:50.66 and that was for the J value of 9 on the 2nd iteration. This was not a very huge improvement as the longest elapsed time was 2:51.60 for the J value of 5 on the 1st iteration. This was all done on the Ireland CDOT machine using the following script with the MegaMek package-------->

##script to change the build values on the cpu to test which is the fastest optimal build setting
rm ~/value.log
for ((j=5; j<=9; j++))
do
mv ~/.rpmmacros ~/.rpmmacros.old
grep -v smp_mflags ~/.rpmmacros.old >~/.rpmmacros
echo "%_smp_mflags -j$j" >>~/.rpmmacros

for ((x=1; x<=3; x++))
do
echo "-j: $j x: $x" >> ~/value.log
echo "build J value $j, iteration $x"
/usr/bin/time -o value.log -a rpmbuild -ba --quiet ~/rpmbuild/SPECS/MegaMek.spec
done
done

---------------------------------------------------------

J Value	Iteration
	1	2	3
5	2:51.60	2:50.75	2:51.15
6	2:50.80	2:51.01	2:50.92
7	2:50.89	2:50.74	2:50.87
8	2:50.86	2:50.82	2:50.71
9	2:50.80	2:50.66	2:50.83