There is no need to use annotative scaling if you are dimensioning in your layout instead of model space.
Your dimensions should be set to "associative" which is NOT the same as annotative. This won't solve the problem if you change the viewport scale however. It will only help if you stretch an object and want the dimensions 1) to follow and 2) to update to the new size.
If you constantly find yourself rescaling viewports then use Annotative Scaling but do so in model space not in paper space.