Yes it is possible to do what you describe. However, when you go from Atlas to Argo you will need to do the patching of the fifth universe and on.
So from what I have understood you find it worthwhile to upgrade to Quartet for 129, but not worthwhile to upgrade to Symphony for 695, which means you appreciate the benefits of Atlas. At least now the product choice lies totally on the project sizes on your side, and not on our side and which features we have chosen to put in the different products. Finally, since you mentioned waiting for next year there are no guarantees that the promotional price of 695 euros will be available. This includes a 30% discount and will be definitely there during the lifetime of Capture Atlas, but maybe not later.
I am in the same situation as Daniel. All of my shows are not big, but they are between 4 and 8 universes. Unfortunately due to the exchange rate in my country, the price to upgrade is very expensive so for now I have a new work around. I will continue to build my show in ago, importing the highly customised stages I am working with, then adding the lighting elements and then will save the show. After that, I will open the show atlas as a demo, which should give me full universes until the session expires. My plan is to keep doing this for a few months until I can pay the huge price to upgrade. Once I have upgraded to the highest extended licence, I hope to never ever have to pay such a large sum of money for an upgrade again. This upgrade alone is almost 1 3rd of the initial price I paid for my licence. :(
Actually, There are a lot of smaller users out here that only use 1,2,4 universes and we are very grateful that the pricing model has changed