When Joe and Bill are in Dave's office, while Joe is holding the rope for Bill to exit onto the ledge outside, all four windows are visible and unobstructed. When the scene changes to an exterior view of the ledge, Mike Johnson, (the jumper, played by Jon Lovitz), is standing with his back squarely in front of a window.
In the first exterior view of the ledge, the view is a long shot with Bill in front of the first window from the left and Mike Johnson, (the jumper, played by Jon Lovitz), in front of the third window from the left. When the shot changes to a close up, Bill is still in front of the same window but Mike is in front of the far-right window, the fourth from the left. As the shots change from near to far, Mike's position changes, far right for close ups and one over for far shots. When the scene changes to an interior of the office, Mike is now in front of the window closer to the center.
When Mr. James looks out the window at Bill standing on the ledge and says, he's stunned by the height and ducks back in, yet in "Daydream" Mr. James sits on the window edge looking out and looks down, and has no problem with the height.