Patterns have always been sized that way. Remember, sizing in the stores has changed quite a bit. An overweight woman will happily spend more for an item that has a label that says it is 2-4 sizes smaller than she really is, even though everyone knows the label is lying!
I like patterns that have multiple sizes on them.
I use an 8-10 pattern but can where a 4-6 if the clothing comes from an expensive store.
Yes, way back when, I would be buying a size 36. Someone had the "brilliant" idea to halve those numbers to make women "feel good", thus creating another issue with self
Trouble with that is, they have continued to change the garment sizing even more, so as to keep us feeling like we are smaller and smaller then we truly are.
This is why I buy clothes at thrift stores and the ones that fit really well I cut up and make in to patterns. If I think about the numbers my head explodes.
Well that is why you do a muslin first isn't it (Or a real garment but out of cheap fabric before you put scissors to the 'spensive stuff)
Have you actually sewn it together yet though. You have to -- not just pinning it. Some patterns lose a lot more than just seam allowances -- built-in facings and button-front overlaps and some kinds of darts and pleats can significantly reduce size. Different pattern styles/companies make different assumptions about how much ease you want. Also remember that fabric shrinks so you may not WANT it to fit just right BEFORE it's been washed a couple times.
Once it is basted together, you can then figure out where/how you need to alter it for your individual figure. And I don't know about other people but me -- and I am not THAT weird shaped -- I pretty reliably have to alter patterns if I want them to sit well on me, unless they are tent-like garments to begin with.
Again, that's why you do a muslin or test garment first
You probably don't have to recut from new fabric -- there are not very many reduction-of-size alterations that can't be done just by snip snip snip on the pieces you've already cut out. Well unless you are trying to match plaids I suppose, I dunno, I avoid that like the plague LOL
But the thing is, once you have got that pattern altered to fit you right, if you have been smart and done the alterations on paper pattern pieces (the originals, or preferably an altered copy) then you HAVE it, you never need to fiddle with it again unless you change shape considerably, you can just blindly use those customized pattern pieces to make twelve different versions of the same shirt (or whatever) and not have to worry any more about the fitting stuff