I betcha thought it was gonna be another one of those "How do I tune to EADG" threads, eh?

Well, it isn't, but it's still a tuning thread.

Alright, I'm looking at the Guitar Pro tab for Blue Monday by Orgy, the cover of New Order's old song, and I'm noticing that the bassist has a five string tuned down half a step, so it's A#D#G#C#F# instead of BEADG.

I don't have a five string, though, I have a normal four stringer. My question is, would I need to tune my four strings to C#(C#G#C#F#) to be able to play the song?

Cause, I know when trying to play a song that has a five string bass in normal tuning, I'd have to drop my E string to D and work the notes for the B on that (Or something to that length, I know my friend who got me into playing bass said it worked, and it does seem to work for me, but I might be doing something else entirely different).
Well, it all depends on how much he uses the low A#,B,and C. If he doesn't use them, you could just tune to DADG and go on. If not, thenyou are gonna have one wobbly low string (unless you have an octave pedal). You might be able to just read to music and play it that way and use your own fingerings if its in Guitar Pro.
Are there any low C# notes in the tab? If not then just tune down a half step and play it on your four.
Yeah, he uses C# quite a bit.

*shrug* I've been in the mindframe of getting a five string for a while to tinker with. Who knows. But the tuning thing has been bugging me for a little while now and almost no one I asked knew what I was talking about or didn't understand what I was trying to ask.