Could it be that it is being suggested that you give the doors a seal of say shellac or a varnish and so stop a mixed stain. By sealing first you may get an even colour throughout so not really staining but puting on a coloured coating. Tinted varnish or the like. It may be that they are carefully choosing wood which whilst ideal structurally may have different absorbions and so you could get a very mixed appearance of colour.. Best wishes.