Thanks @Douglas. I misspoke when I said using increments was unnecessarily complex. I meant to say that using increments is not a good fit for the issue that I am trying to address.
I understand how to use increments the way you did, it is just not the way I would choose to do it. And note that if I use waist_circ * 1.1 I am adding 10 percent of WHATEVER the waist circumference is, independent on what set of measurements I choose. My point is that I want the formula to be scalable among the most diverse group possible. (and yes, I know that in many or most patterns one will deal with 1/4 of the waist circumference in any given pattern piece).
So, it is great that you have posted an example of how to use increments and it will work for the two examples you gave (Wolf_W_12 and Wolf_W_18).
Now, imagine for a moment that you want to use your pattern to make a garment for a fashion doll which has the same proportions as the Wolf_W_12 model and whose height is 12 inches. It is “easey” to see that adding 2 inches of wearing ease around a waist that small would not give the results one might expect.
So, what I do when I create a pattern, is attempt to make all of the adjustments (like wearing ease) using a formula that is proportional to the actual size of the model. If the model has a 30 inch waist, then multiplying by 1.1 will give 3 inches of wearing ease (adjusted measurement is 33"). If the model has a 24" waist, the formula gives 2.4 inches of ease, adjusted measurement is 26.4"). If the model has a 2 1/2 inch waist (visualize a barbie doll) the model will give 0.25 (a quarter inch) of wearing ease for an adjusted measurement of 2.75 inches.
I am trying to demonstrate that the only value in using #ease in the formula would be making the formula more readable to a human. It may be a good idea for that reason alone. I am also trying to illustrate that using a formula that ADDS ease will work for only a limited portion of the potential models that may be in the target audience. That is why I prefer to use a multiplier rather than an added value. In fact, I assert that if you want to ADD an ease constant, the increment table in the pattern file is NOT an ideal place to keep it. Because it is so dependent on the size of the target, it would be better to use a custom measurement and store it in the .vit file.