It does sound perplexing. I have the tailor pin mine while I'm trying on with the highest shoe I expect to wear. I generally think they are doing it as pinned.
I have found, though, that where the pants fall on my waist can vary a lot, say if I wear belted or not, and also, finally, it dawned on my that there might be some shrinkage after drycleaning. So, I do try to build this in.
The downside is that I have some pants that reallly can't tolerate even a half-inch different shoe height and still look the way I want. This became more or an issue when I began acquiring some more fun and modern shoes that theoretically would go well with several pairs of pants, but introduced slightly varying heel heights.
My main solution has been that I have to keep this in mind both with hemming and with new shoe options. Such as, trying to keep shoes at about 2 different heights--flat and maybe 1 1/2 " heel. For some pants, it's not hard to have multiple lengths--not necessarily exact dupes, but similar silhouettes--especially in black.
For other pants, I bring them home and put them through shoe paces--need to be able to wear with 2 different--would like even more mix and match but am finding the most important thing is to get a good match with a couple, and then have PPL for that.
Also I find PPL is so dependend on the shoe vamp and the pant width at the hem. Just pant length alone does not make some pants and shoes good companions. That also has influenced what makes a good shoe addition for me and vice versa, whether a pair of pants that seems versatile at first glance, will hang up on the very shoes I thought I'd use.
