Video Slot wording

I've always been a bit of a stickler for using unambiguous language wherever possible, so as you can imagine, I'm always a little disappointed with the wording used by slot manufacturers within their paytable and bonus descriptions. There's one statement that I'm seeing more and more of, mostly (or maybe exclusively, can't remember) in WMS games that reads, blah, blah, blah, "...each reel contains a number of adjacent positions that, before the reel spin stops, are randomly replaced with a symbol from the paytable except...", Bonus/Feature/etc.

There are a number of ways I can see to interpret this, all of which affect my understanding of how the game in question works. Ultimately, I know this still gets worked into the payback percentage of the machine, but it would be nice to understand exactly what the game developers and marketers are actually trying to describe here.

Does anyone have a definitive correct interpretation of what the statement above means?

Thanks!

It means there's a section of each virtual reel where there is a placeholder symbol. That placeholder is randomly replaced with a single game symbol before each spin. Many game vendors use a similar technique. For example:
https://www.google.com/patents/US8096869