There is nothing wrong if everything is clearly specified like stock:water = 1:1 or stock:final volume = 1:2. However people tend to assume former in many photographic contexts without making it explicit.(posted 8375 days ago)I prefer notation 1+(n-1) for 1/n concentration. However, in this context one usually restrict n to positive integer, although dilution makes sense for any proportion (real number) between 0 and 1, inclusive.
It is a bit inconvenient when most formulae are published in metric units some tanks and packaged chemicals assume Imperial system. Developers like HC-110 and Ilfotec HC usually specify dilution in 1:(n-1) or 1+(n-1) fashion where n is a power of 2. At the same time, some film tanks come in metric scale. For example, mixing 1+63 for 1 liter tank requires 15.625 (or 15 + 5/8) ml concentrate.
In my personal records, partly because the capacities of my tank and print slot processor are specified in metric volume units, I am shifting into notation like concentration 0.015 and calibrate time and temperature accordingly. (1+63 dilution would be 0.015625 concentration although maintaining five significant digits is not practical nor useful) In some cases I need to make 473 ml working solution - I can simply multiply 0.015 and 473 to get approximately 7.1 ml concentrate and WTM 473 ml (yes number comes out messy this case).
Many formulae still begin with some fraction of water and after dissolving everything another water to make the final specified volume. Either way, when precision is important chemists specify in molarity or other appropriate units, and in most photographic applications generally moderate requirement for precision does not neccesiate that kind of units.