Also, as I followed your math, I think I saw an error.
300R across 5V will conduct 5/300 = 0.0017 A, or 1.7mA.
I tried 3K with 5V and 5/3000 = 1.66mA, so 5/300 = 16.6mA, not 1.66mA (or 1.7mA).
You're right. Thanks for pointing that out. It might have confused someone. Clearly, I was one of them!