Akiria is retarded and is known for backtracking. The fact that you said "recently" acknowledges this.
Edit: Now that a new series is coming out Toriyama is going to be saying a whole lot of shyt that doesn't make sense because he doesn't want to be constricted to the laws of Dbz.
All the Androids in DBZ were only as strong as they were designed to be. Saying they can become stronger just by training is stupid. I wouldn't be surprised is Toriyama "recently" said this though.
He said something of the sort regarding 17 and 18 since they were technically Cyborgs, not full Androids. Since they have a "human" base they can get stronger from training... Cell is a pure Android like 16 so they don't get stronger via training. Makes sense in the DBZ universe, I guess