Not exactly correct, you can start enjoying it immediately.
People run slides because, you know, because they read about it and want to give their plasma some love. There is no evidence laid out that I know of that says it's better.
The idea is that the phosphors wear out the very quickest at the beginning, and over its life the wear is slower and slower. I mean... if you are nuts, you could re-calibrate every 1000 hours, just like um, some people change their oil every 1000 miles in their sports vehicle.
IOW, you can just opt to run the tv for whatever they say, 120 hours, 200 hours, etc, before you run your calibration. (So, that's the main point; the slides just help for best wear in evenness, but . . . would I do it? I dunno TBH).
Hey, I've just been researching a little bit on calibration devices+colorimeters+software, which would probably be $3k plus, and the main benefit for me would be to dial down some oversaturated green. Hey, it's totally nuts, but I was figuring out if there was a way I can give my display some love. Don't take what crazy people do as the bare minimum by any means. REMEMBER: just the fact that you will even calibrate ONCE is already more than what 99% of what people do!!
Cheers.