rainborick - 8:17 pm on Feb 5, 2012 (gmt 0)
Of course, the primary loss would be from links pointing to the page from external sites. If you update your internal links, there would be no loss since Google would eventually discover all of the changes. I think we have to assume that the 15% figure was somebody's estimate, anyway. You're bound to see a drop in performance from that page until Google absorbs it all, but I don't think it's worth worrying about. If the move makes sense, then PageRank should not be a factor in your decision.