No doubt. Where Nightwish is concerned, waiting = a mistake.
I almost missed the 2004 tour because i didn't try for a ticket until fairly late. Ticketmaster online had none. Though for some reason when i called up the voice ordering system, they had a ticket available. I don't see why one would have and the other wouldn't (especially when i called not 60 seconds after checking the online) but i wasn't about to complain. ;]
Ever since then, i have made it a practice to order my tickets as soon as they go on sale (though i understand that in some situations, such as yours C, it may not be practical to order months in advance).