Support for Indie Authors discussion

I have a two-volume story on Kindle and (anecdotally, I haven't done the stats properly) it seems that when I sell volume 1 I either sell the same quantity of volume 2 at the same time, or the same quantity almost exactly a month later. So some readers are buying both at once, some are taking a month to read 1 then buying 2, but there is very little in between.

Has anyone else noticed this sort of pattern?

Someone else told me that if they had a giveaway of one of the books in a series, it stimulated sales in the rest of the books in that series at full price. Hoping that is the case. I'm launching book two soon.