Why do you offer white in your range of watercolours. Surely a watercolourist would have no need for white.
As we concentrate on obtaining the widest range of mixes from a limited palette I consider white to be essential, in all media. The inclusion of white paint in a mix will always dull and 'cool' other colours, it will also make otherwise transparent colours more opaque.
Consider a colour such as Naples Yellow, which is essentially a mix of Cadmium Yellow and White. It is important to realize that it is impossible to mix such a colour without the use of white. As this is such a vital area I have covered it in more detail in the Articles section. One thing is certain, by abandoning white in your palette you effectively remove half of the available tints.