Personal anecdotal suggestion here…when I’m starting a new vial I usually assume it’s what it’s supposed to be (if it’s supposed to be 20mg I assume it’s 20mg) then when calculating out my desired dose, I do just slightly under what I’d actually want. So if I want 4mg per dose and that’s 40units, I’d do like 35-38 units for my first dose of that vial and see how it feels. If it doesn’t give the strength of effects I want, I increase to 40units. And play with the numbers every time based on how I felt. It’s like cooking vs baking lol measure with your heart darlin but that’s why I buy the 30 and 50 unit syringes because small incremental changes like that are easier to measure. I only do that for my GLP of choice though (Reta for me) but if it’s glow or selank or something I just assume it is what it says and use as planned…right or wrong 🤷♀️