If elevated (less than 2x normal) liver enzymes go down to normal range does it mean that damaging activity stopped? in nash or ald?

Not necessarily: unfortunately, certain forms of liver disease can be active with little or no liver enzyme elevation. However, ff you were told you have NASH, and previously had elevated enzymes, then their return to normal is a good sign. As you may know, the most important treatments are weight loss, abstinence from alcohol and control of diabetes and hyperlipidemia, if you have those.

Yes: Yes it does mean that damage is stopped. But needs to be careful and to identify the precipitating factor.