Suppose you're reading a biography of Huygens. You may find yourself inspired to memorize a few of the basic facts therein. Dutifully, you feed his life's dates, his major acquaintances and maybe a few places of importance into the SR system of your choice. You are committed and keep repeating those facts in ever-increasing intervals.
After a few years a random conversation touches upon the very subject. To your delight you discover that you are able to hold forth on Huygens, the man and his time.
To your surprise (and this is my contention [and experience]), you also find yourself able to speak with some level of accuracy about tangential matter -- eg. the theories he worked on -- without ever having either added related facts to the database or dealt with the subject matter in the intervening years.
In other words: recall of a whole web of interconnected pieces of knowledge may be strengthened considerably by spaced repetition of just a few of the central facts.
In my experience there's no specific 'encoding' procedure necessary. I never put any thought into carefully selecting facts for the spaced repetition treatment, yet the effect usually manifested itself. So, yes, I would say it's a 'recall' phenomenon inasmuch as the brain does all the heavy lifting.