Check disk example problem

Hello,
nice plugins. I found one problem:
Example for checking disk suggest using limits for “disk full”:
perl check_linux_stats.pl -D -w 95 -c 100 -u % -p /tmp,/usr,/var
but plugins uses limits for “disk free”:
[krizb@kriznb linux]$ df -h /var
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/vg0-varF 4.9G 3.2G 1.5G 69% /var
[krizb@kriznb linux]$ /usr/lib64/nagios/plugins/check_linux_stats.pl -D -w 95 -c 100 -u % -p /var
DISK CRITICAL used : /var 30.47% free | /var=3322124KB
[krizb@kriznb linux]$ /usr/lib64/nagios/plugins/check_linux_stats.pl -D -w 5 -c 0 -u % -p /var
DISK OK used : /var 30.47% free | /var=3322124KB
[krizb@kriznb linux]$