I dont see why not but would take up 3 blfs. Why not use some speed dials?
I think there is going to be a better PBX status indication in V10 if this is what you are trying to achieve.
Also in V10 there is going to be better in/out of hours control at more granular levels so hopefully you wont need to use that code. We have only used it once on all our customers as they wanted to close at midday on the day before thanksgiving and we didnt want to change hours and couldnt do a half day holiday. The problem with most people using this code is people forget they used it and wonder why their phones dont ring on the monday morning. So we manage it for them in the cases they want to use it.