Installation in a wooden ceiling is simply something different than in a concrete ceiling. Here, fire protection boxes are installed in the ceiling, which are simply more expensive, and in the upper floor the ceiling may need to be suspended to maintain distance from the foil. Heat generation is no longer such an issue with LED as it was with halogen lamps, but many lamp manufacturers still use their old approvals, so the expensive boxes still have to be installed. That’s where the price from Doc comes from...
Simply planning light outlets and retrofitting them yourself is definitely cheaper and is also likely to work (furniture lights are quite suitable). Normally, the lamp is anyway in non-combustible materials and in the worst case, you lower the foil a bit. BUT in the event of an insurance claim, they will ask you about the approval!