For that scenario i'd still recommend the workflow i suggested in my previous post. That is, if you want to only have to buy one copy of PowerCMS 2 that you would store on your localhost for making updates.
You could always buy a PowerCMS 2 license specific to the site that you need to make changes to, but if you have a lot of sites, that can get pretty pricey - i understand!
One thing to keep in mind is that Site Sculptor's CMS does have the ability to create new pages based on a template which could be sufficient for many of the sites you create. You just need to plan accordingly in Site Sculptor and specify the correct pages to be used as a content management template.
I've discussed this a little further in this thread here: showthread.php?t=13381
Hope this helps!