One thing I’ve learned over the years is I get what I get.
I used to stress about hitting the exact numbers. Now, +/- 1/2 gal, a few degrees here or there, a gravity point or two between friends is fine in my brewery.
Environmental conditions such as grain moisture, humidity, pressure, temp, etc. or even recipe design such as more/less hops, grain, etc. can play a larger roll in the outcome than I care to calculate.
Precision is no longer required or expected around here. I just do the math on what I get. I don’t run such a tight budget or QA spec that it matters. I do this for fun and something to drink when the day is done.
Close enough is good enough. Cheers!