I did a little background research and found out that this particular piece was composed in 1804 and dedicated to count Ferdinand von Waldstein.Let's get right down to it. I did the specific roman numeral analysis as requested by the workbook, so let's do that first.
Just so you know that I know, all of the chords with a b or a # in front of it is a mixture chord.
When the main motive occurs again at measure 156, it is almost identical save for the chord at the fermata. This is a V chord in the first occurence, but a bVI chord in the second. This, to paraphrase the workbook, creates a "sensation of surprise." This sensation occurs because the listener has already heard the motive the first time (and, for almost all of us, we've probably heard this piece before, anyway...), and therefore the motive has already left an impression on the listener. When it resolves to a bVI then, the listener is at least intrigued.
When the motive is finally heard again, it is in the last 8 measures of the piece. At this point it is like the music is trying to retreat from the listener's ear. The similar sections appear an octave higher. The dynamics are also worthy of note, as well as the chords, which are similar, but not the same as before.
I don't know what else to put, or if I'm doing this right or not! (Maybe you could give me a few pointers...)