When they match, you, are they matching on your face or on the inside of your wrist? When I color matched folks, I would look at their face yes but I usually started my initial matching on the inside of the wrist because to me, it gave a more accurate read for the undertones, because people do have issues with redness, or acne or fine lines that might give an impression of a different shade or tone, and what is best for them.
What I would do is match it to about 3 to 4 on the wrist with an a range and then strip those on the cheek and consult with a customer and say hey which one do you think match is best because honestly there at the end of the day they’re the one wearing it so I would get it within a specific range that I thought would be best for them and then leave the final pick up them.
Some customers hated this technique and some appreciate it so you know it was hit or miss for me go, but I felt more confident and getting the customer to a shade that they liked and we’re comfortable wearing day today using that method.
Edit- clarity
High magnification mirror and bright lighting. I also have hand tremors and shaking, and I’ve been using the new line of brushes by Selma Blair and they’re pretty amazing.