Using the Starting Strength standards found here (pdf link), and the 1 Rep Max Calculator found here, I can finally say that I've reached Category IV (Advanced) for Squats at 165 lbs. bodyweight.

I did 280 lbs. Squats today for 3 sets of 8, 7, 7. The 1 rep max calculator at 280x8 estimates a 1RM of 250. The Starting Strength standard for Category IV at 165lbs bodyweight is 344 lbs. 1RM. And yes, my form was good. I go down below parallel for my squats.

Bench Press: 195 lbs. for 8 reps. Estimated 1RM is 244. Starting Strength Category IV for bodyweight 165 starts at 255. Not quite there yet.

Deadlift: 335 lbs. for 8 reps. Estimated 1RM is 419. Starting Strength Category IV for bodyweight 165 starts at 411. Looks like I made it! However, before I go claiming this weight, I don't actually do Deadlifts for 8 reps. I only train Romanian Deadlifts. So my estimate is not entirely 1-to-1. You shouldn't really be training Deadlifts for 3 sets of 8, though.

The weights listed above are only estimates for what my 1 rep max would be based on reps and weight used. Generally, the higher the rep range plugged into the calculator, the less accurate the estimate is. 8 reps is a little on the higher side, and therefore not quite as reliable as an estimate based on 5 or 6 reps. I don't actually know that my real 1RM for Squats is 350.

So what are my real 1RMs?

I've only tested them once, back in March of this year. At the slightly higher weight of 170, here are my 1RMs at the time:

Bench Press: 245

Squat: 325

Deadlift: 405

If I can hold onto my bench press 1RM at my current weight, I  would finally be in Category IV. It's worth noting that my actual 1RMs are lower than my estimates. The main reason is that my estimates at the time were also lower. I wasn't squatting 280; I was squatting 265. 

The other, more important reason, is that it is not usually recommended to test your actual 1RMs. Pushing or pulling weight that your body can only handle for 1 rep can be dangerous. The last thing you want is an injury that prevents you from lifting. For this reason, it's not likely that I'll test my actual 1RMs more than once or twice a year, and only for the next few years or so. I'm happy using the estimates, as I can see from personal experience that they are actually pretty accurate.