As said before, weights do tend to go up from early calculations and test boats, when brochures are made, I wonder why. ..
Once a builder have commented that with me. When a boat is designed by an Architect they make weight calculations based on the optimal use of materials.
Optimizing materials is an expensive process that is mostly done in what regards racing were the cost is not that important. They are going to make an one off and the boat is going to be expensive anyway. When you want to produce a boat cost becomes a major issue and maximizing materials to the limit is not an absolute priority anymore. Yes they will try to maximize materials if it is not too expensive taking into consideration production costs.
That's why on production boats the weight is rarely the one specified by the designer and why more expensive boats can be lighter even using the same material: Costs considerations on production regarding difficult execution and control of quality to obtain the strength/weight required by the designer. More expensive boats have a bigger margin in what concerns that cost consideration.
I remember that some years ago Bavaria had a very fast line of boats called Match. They had problems with the keels of the 42 and abandoned the project. It turned out that for producing a boat were the materials are optimized you have to have a quality control that is hard to get on a big production line or impossible without a substantial increase in costs. Optimizing materials gives no place for any mistake in the production.
I remember also, and I was impressed by it, that on the Salona shipyard they showed to me that they use transparent gelcoat bellow the water line on the lighter boats (vacuum infused boats) to be sure that there are no minor flaws on the laminate. Quality control is a big issue when you maximize materials because a mistake or a defect can have drastic consequences and the Salonas are not extremely light, the 41 weights between 7200 and 6600kg (vacuum infused boat with lighter material interior) and that without keel will be 4800 to 4200Kg, values that on the lighter version are not as good as the ones from Opium but better than the ones from Azuree even on the fast version.
Here you can see, on the right side of the image, that bottom clear gel-coat that permits to see all the laminate behind:
Of course we have to take into consideration that the Azuree is a more beamy boat and that therefore the hull will weight more but also that the Salona has an interior stainless steel frame that redistributes all keel and shrouds efforts by the hull. I don't know if the weigh of the frame compensates what they can win on the hull weight, but that will give a bigger safety margin on the more critical points of a light sailboat: Keel and shrouds attachments to the hull.