Just a theory.
Run ./asyncron.sh for an idea of how this is supposed to work.
$ ps aux | grep async | grep -v grep
steve 21881 5.8 0.2 2474520 8612 s000 S+ 12:48AM 0:00.09 /usr/bin/php ./asynccron.php run foo9751
steve 21324 0.0 0.2 2474520 8624 s000 S+ 12:47AM 0:00.10 /usr/bin/php ./asynccron.php run foo44
steve 21311 0.0 0.2 2474520 8688 s000 S+ 12:47AM 0:00.09 /usr/bin/php ./asynccron.php run foo7227
steve 21298 0.0 0.2 2474520 8636 s000 S+ 12:47AM 0:00.09 /usr/bin/php ./asynccron.php run foo3547
steve 21285 0.0 0.2 2466328 8632 s000 S+ 12:47AM 0:00.09 /usr/bin/php ./asynccron.php run foo9047
steve 21272 0.0 0.2 2474520 8644 s000 S+ 12:47AM 0:00.09 /usr/bin/php ./asynccron.php run foo9470
steve 21259 0.0 0.2 2474520 8616 s000 S+ 12:47AM 0:00.09 /usr/bin/php ./asynccron.php run foo2037
steve 21246 0.0 0.2 2473496 8668 s000 S+ 12:47AM 0:00.09 /usr/bin/php ./asynccron.php run foo8222
steve 21233 0.0 0.2 2473496 8672 s000 S+ 12:47AM 0:00.10 /usr/bin/php ./asynccron.php run foo7564
steve 21220 0.0 0.2 2474520 8608 s000 S+ 12:47AM 0:00.09 /usr/bin/php ./asynccron.php run foo907
steve 21207 0.0 0.2 2474520 8628 s000 S+ 12:46AM 0:00.09 /usr/bin/php ./asynccron.php run foo2728
steve 21181 0.0 0.2 2474520 8612 s000 S+ 12:46AM 0:00.09 /usr/bin/php ./asynccron.php run foo8312
steve 21168 0.0 0.2 2474520 8652 s000 S+ 12:46AM 0:00.11 /usr/bin/php ./asynccron.php run foo6682
steve 21129 0.0 0.2 2466328 8604 s000 S+ 12:46AM 0:00.09 /usr/bin/php ./asynccron.php run foo1596
steve 21116 0.0 0.2 2467352 8612 s000 S+ 12:46AM 0:00.09 /usr/bin/php ./asynccron.php run foo4191
steve 21103 0.0 0.2 2475544 8616 s000 S+ 12:46AM 0:00.10 /usr/bin/php ./asynccron.php run foo359
steve 21090 0.0 0.2 2466328 8628 s000 S+ 12:46AM 0:00.09 /usr/bin/php ./asynccron.php run foo8751
steve 21077 0.0 0.2 2467352 8628 s000 S+ 12:46AM 0:00.10 /usr/bin/php ./asynccron.php run foo4175
steve 21061 0.0 0.0 2444632 1052 s000 S+ 12:46AM 0:00.13 /bin/sh ./asynccron.sh
steve 21846 0.0 0.2 2467352 8600 s000 S+ 12:47AM 0:00.09 /usr/bin/php ./asynccron.php run foo9579
steve 21480 0.0 0.2 2459160 8604 s000 S+ 12:47AM 0:00.09 /usr/bin/php ./asynccron.php run foo5062