not at all! and i believe i could even increase that yeild to a lb with the 400hps. i am currently on probation for 1 year but when i do start up my grow again i will do a few things differently. i have already built a cool tube for the light and have been doing alot of reasearch on different hydro techniques (dwc, aero) i do have a few guerrilla sites that i am playing with! i just couldn't give it up all together, just not in my home where a probation officer could just drop by at any time.

anyway, if you do go scrog a big problem that i had to deal with was when the buds start to fill the screen they tend to form barrier that can block airflow from below to above the screen. i had to add an extra intake fan just above the screen to deal with this. i just used a 4inch inline fan and it solved the prob. completely.
another thing that i learned from experience is to remove fan leaves sparingly and ONLY ABOVE THE SCREEN. i would cut any fanleave leaves that were shading budsites and could not be tucked under the screen. i would not remove any below the screen(alot will die and fall on there own anyway) with one grow i removed alot more fan leaves than usual, trying to make sure every single budsite had full light and also removing growth below the the screen. the theory being that the plant would consintrate(spelling?) on the buds above the screen if there was no growth below. the result was lower quality, more leafy and airy buds at harvest! well, i hope these few tips help a little. there is no sense in you figuring it out the hard way when i already did!