A's and a's in auto adjustments

In using the small a's (the one in the exposure tab) to do auto exposure adjustments, it will only change the exposure value and leaving the contrast,brightness and saturation value untouched. However if I use the BIG A's (the one in the tool bar) to do auto adjustments it will (or may) change all the values in the exposure tab. I thought by using auto in the tab it will (or may) change all values inside the tab and if I just want to adjust a particular value I will move that slider only. Am I missing something or is that auto in exposure tab will only adjust exposure and nothing else ?

Thanks for looking and your input.