Well, you didn't mention that she owns the company, I thought she was an employee.
I think you can ask an employee to do a nixer, not the owner. But you can say you'd like a design only and she might do that for a certain price.
Even when companies charge for designs they are not necessarily charging the full commercial price of the design.. as evidenced by the fact that an interior designer will charge more. Maybe an interior designer does more however which would allow for a higher price.
One poster above says that their high end kitchen company charges 40 Euro.. that must be less than it actually costs the company to do the design, the same with 100 Euro in my opinion, especially for computer drawn custom or bespoke cabinets, not standard 600mm units.
Companies are charging for designs, to be refunded if going ahead, to get rid of timewasters, that's obvious.. otherwise everyone would get a design if it was free. The large mass producers who do designs for free are the ones where they just put in the standard cabinets everywhere.. they can do this as they usually have full time designers anyway, and they usually do the design while you're there talking to them.. so it's a necessary part of their sales process.