@quickNir, Being one of the main posters who keeps harping on the sample size being inadequate, I feel the need to defend my position.
Early on (close to a year ago now) my anecdotal experience was suggesting to me that I was getting too few successes for each RE. So I began logging every attempt at REing a green at 20% and every attempt at REing a blue at 10% (I was mainly focusing on Armormech and Synthweaving at the time).
After 200 tries, I was way off of expected results
After 400 tries, it was still off, but better
After 600 tries, I was starting to reach the 20% and 10% respectively
I stopped tracking shortly thereafter, as the more I did the closer I reached 20%/10%. This was adequate for my purposes.
Please notice the title of this thread is: "Reverse Engineering is not 20%"
The OPs sample size is adequate to prove that HE wasn't getting 20%. It is NOT adequate to prove that everyone else isn't getting 20% either.
This statement that he made:
With the mean sample is out of the 99.7 boundary that mean that it is almost impossible that the 20 percent is the true rate of getting a new plan.
At only 400-odd samples in his raw data, it wouldn't take very many successes in a row to bring his data above the 99.7. Cleet_Xia (post 29) pointed out that 3 more successes would bring the results within the boundary.
Now, my most significant objection with the sample size is a purely practical one:
If Bioware has, in fact, incorrectly implemented RNG and it is not actually working at the stated 20%, they will need a lot more data than the OP has provided to look into it.
Does anyone really believe that those 400 points of data is "proof" that the 20% is wrong? Really? And that based on this alone the devs should believe it is broken? Really really? Seriously?
If the OP instead was asking for others to log their RE results and add them to this thread, and collectively a broader picture started to form, THAT would be useful. But that's not what happened. Data was gotten; a conclusion was formed; it was briefly defended; and that was it.