As i understand it, this is simply a random chance based upon the tier of the monster. If this is so, then it is seriously broken. I, and my guildmate from Misfits of Mischief, have killed at LEAST 1000 level 90+ mobs, and we got our first form drop on Sunday! Still not one tech! Which is even worse! I personnally have killed thousands of level 80s and have I seen 1 tier 4 tech? No!
It may be that it is only particular mobs that drop forms and techs, if so, then say so here!