I agree with the other physician, I would not panic at 3 weeks and start thinking about revisions.
ALL PATIENTS have pre-existing asymmetries of their breasts and it is important to point them out in detail because many of the asymmetries CANNOT be fixed by breast augmentation alone. For example, the nipple position is slightly different (as it is in most patients) and that was undoubtedly there prior to breast augmentation.
I do not put that much stock in breast sizers...They always slightly "overestimate" the size that a patient can expect. I see this more of a problem with silicone gel than saline implants and typically have to go "plus 1" size from the sizers for patients to be happy. I also believe in using a sterile breast sizer at the time of surgery because there really is not better and more accurate place to determine the best implant size for that patient's tissues than at surgery.
I personally do not favor shaped, "teardrop", or anatomic implants but that does not mean that some surgeons get excellent results with them.
It doesn't appear that the left breast is much smaller and it takes a complete 3 months for implants to settle downward even with doing implant displacement exercises...the only thing in your case is that the textured anatomic implants won't settle as much as a smooth round implant because it "locks into" the capsule, but at 3 weeks the capsule is still not completely formed so it is still worth being aggressive with implant displacement exercises.
Even if you needed an "exchange of implants" which I would consider at 3 months if you were still unhappy with either size or position of the implants, the exchange is even a faster recovery for the patients as your tissues are already "stretched" and switching out implants even if you decided on a slightly bigger smooth round silicone gel implant wound not be difficult and you would do fine with that.
Realize that no women's breasts are perfect mirror images of each other and no breast augmentation can give you that. Wait and see where you are at 3 months and then talk with your surgeon about your options.
I hope this helps!