It should be, and I'd be interested if you have a reproducible case where it isn't. Where it definitely is not robust at this time is if you dimension in LayOut, then make a bunch of geometry changes in SketchUp to the model. The points we attach to in your 3D model are not persistent / uniquely ID'd so that we can say that we can find the point you wanted after the geometry changed. For this reason, we'd recommend doing dimensions after the modeling has settled down.
Anything more specific? Modes of how to update the model, or workflow? We'd also suggest turning auto rendering off, and controlling model rendering yourself for larger documents (when there are model changes); you can right click on a page with dirty models and select "Render Models on Page".
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