Yes, you're missing the math.
Again: I can't put more plants in 1.2mx1.2m cabinet than I can now, can I? Right now there's 1 DP AWW and in a couple of days I will add another plant as per your advice in private message. That's about it. I have 2x MS0006s there. If I upgrade them it will pay off the upgrade cost in 61 months or FIVE YEARS. I purchased my current lights little over 1 month ago. Wanna bet on 1 dollar/pound there will be newer and better lights in 5 years? So far I don't see anything other than marketing here. If there were new complete light fixtures with these new rebels - fine. But upgrade is not worth it.