the 150 yeilds 5oz, it was just the 1st time that i only got 3.5. i vegged for about 4-6 weeks usually. then i would move the plants from the veg room and put them under the screen. i would leave the lights on 18/6 until the screen was 60-80% full (strain dependent) then switch to 12/12. i found with scrog in small spaces it would be in your best interest to ad a second intake fan above the screen because as the buds thicken late in flower they tend to form a wall that blocks ventillation from below to above the screen. i used a 4inch inline fan(the 30$ ones) for this and it made all the difference in the world.

here are a few pics of the 150hps scrog set up (2ftx2ftx2.5ft) the left side is the 150hps and the right side had about 350 of cfls.