You're correct. I mis-stated that. He did pre-record his part of the "Is There Anybody Out There?" intro, but he performed the vocal and guitar solos live at the top of the Wall. And you're absolutely right - he repeated half of the first chorus rather than doing the lines of the second one...
<p><b>Roger Waters The Wall Blu-ray Review - Recommended</b></p>
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<p><em>Roger Waters The Wall</em> is built onto Blu-ray and offers home theater viewers a chance to experience one of the greatest rock concert experiences ever created. Fans of Pink Floyd and of Waters will want to...