I'm close to pulling the trigger on a Panasonic Arc 5, would be used to shave my head (currently using a disposable blade).... have spent several hours online researching the Arc 5 vs Braun vs etc.... so, my question is, i think during my research i saw it mentioned somewhere that the older generation Arc5 (the ES LV 65S and 95S) had a "sensor" which, if manually activated, would cycle the power up/down depending on how it senses your hair thickness/density etc....meaning it would raise power a bit when you're going over your thicker hairs. Then i think i read that the newer generation (ES LV 9N and 6N) have the same "sensor" feature but it's not user-adjustable, meaning (i think ?) that it's permanently "on" .... can anyone clarify this for me ? Personally, i want control over this function at all times. TIA for any feedback on this !!