How do the "base" lofts of these clubs, for example a 15 degree 910F, relate to the loft adjustments you can make through the adjustable hosel? If you start with the base 15 degrees, can you adjust it to 13 or 17, etc. I would assume not, or else you wouldn't have several "base" lofts, so how exactly do these two approaches to varying lofts work?