Why extra checks on top of critical threshold checks ?

[gamato]

Why is there an extra check / condition in some commands apart from warning / critical thresholds please ?
For instance in 'cputemp' the script checks for 89 and prints out "CPU temperature too high!" instead of standard "CRITICAL" message. The same is there for 'temp' and 'hd#temp' commands.
Why is it so and how were the numbers chosen please ?
PS: There's even a bug in 'temp' command where the code checks for special value '89' but NAGIOS output has '80' at the end.