The closest thing to true randomness is atmospheric noise, I imagine Jagex test their in-house generator with a Chi-square test. I've seen people get back-to-back tassets at Bandos so the theory about that goes out of the window. The fact you got drops after almost every update is not proof of anything, I could go kill 2 abyssal demons and get 2 whips, thus proving the drop rate is 100% right?