I'd keep going till you miss a rep. If you've never missed, your perception of your ability level will be off. Even when you miss, it's quite possible you had more in you.
I missed 330 on the last rep, my coach basically told me I gave up too easily because I wasn't used to really heavy weights. I nailed 335 the next workout.
Basically, what feels like a max effort is probably not. Take some video of your squat, and compare it to Austin Baraki's 600 squat/650 deadlift video to see what I'm talking about.