There are a few ways you can dimension with layouts and detail views. I expect you have multiple detail views showing multiple scales on one layout.
- If both the dimensions and the objects exist in the detailed view, then the Annotation Scaling Property should take care of the dimension scale so all the dimensions ares scaled the same. You can make sure this option is on in Tools pulldown > Options > Annotation. To the right you can Enable Scaling and set model space Scale 1.0. These also happen to be the defaults.
- If the objects are within the detailed view and the dimensions exist out in the layout, then the dimension style sizes for arrows and dimension lines will control the size of the dimensions.
What can be confusing is when the size of the Dimensions in standard Front, Top, Right and Perspective working Viewports does not match the scale that is in the layouts. Normally it is difficult to setup dimensions in the working viewports and predict exactly what will happen within layout views.
Does this help, or is there another aspect of dimensions that do not make sense?