So I bought one of the Apple Rechargeable Battery kits and fully charged up all six batteries that came with it. My Magic Mouse just now reported that its batteries were running low, so I removed the old, depleted Energizer InfoLithium batteries (which, when new, have always showed 100% battery level on the mouse's control panel) and installed a set of the Apple rechargeables. Result: The mouse's control panel shows 74% battery level. Tried another set of the rechargeable batteries and got the same result. Am I correct in assuming that this discrepancy is occurring because of the difference between non-rechargeable lithiums and rechargeables? Has anyone else seen this?