When I multiply 110 * 0.67 I get 73.7 rounding to 74, so I would say the 1/3 break is at 1.074.
Yeast may be able to divide and multiply, but they don't get stressed about the math and neither should we. I don't think they will care if the gravity is 1.074, 1.077 or 1.065 for that matter. As long as they are getting their nutrients staggered in over time and get enough, I think they will be happy.