problem with setting time window for alerts

I'm apparently doing something extremely wrong trying to set a time window for alerts for a specific server. This server burns up cpu every night and we don't want to see alarms for it, so I tried doing this to block those alarms in my hosts.cfg file -

IP   servername # conn NKTIME=*:0800:2200

I thought this was working but all of a sudden this weekend we got a ton of alarms from it again during the night.