The timing of when Alicia entered the organization's ranks is not an issue. Alicia's agent tells her that she is the "strongest in our annals," (vol9, ch49) which I took to mean strongest of all recorded Claymores. This makes sense when we find out that she can fight fully awakened, but this latest extra scene has Teresa taking down an awakened former #1 rather handily.

I think that the author is saying that Teresa was really that good, and that her handler's comment of "there's no way that it would end well against an awakened, former number one" works to have the organization underestimate her actual strength.



On a side note, if we were to find the time of when Alicia enters the Organization:
She and Beth could possibly be the twins mentioned in vol12, ch64. We see Raphaela meeting with Teresa later that chapter, so Alicia + Beth were probably already under development in Teresa's era.

( suddenly... I feel very nerdy for leafing through the archives and uploading the manga pics >< )