The downloads limits are set per download purchase. For example, say you had download limit: 4, ip limit: 1, time limit: 2 weeks. When purchased Product A could be downloaded 4 times from one IP address up to 2 weeks after purchase. John would face a restriction whenever he downloaded it more than 4 times, attempted to download it from a 2nd IP, or downloaded after 2 weeks from purchase (whatever condition came first). If John purchases another product B, his downloads of Product A have no affect on the download limits of Product B.