While your current result may not be what is most desirable to you, given the details you are reporting about your surgery, it is completely conceivable, and actually expected. I think that a 50 cc difference in saline implants can in fact be very noticeable for many reasons, not just volume difference. This is especially true if any pre-existing volume differences between the breasts were misjudged and the incorrect actions were taken at surgery, namely, adding more saline to a breast which really didn't need that much more. This will just serve to accentuate the problem. But probably more important than the volume difference are the differences in dimension and tone that the additional saline will create. These implants have a set base dimension and projection height, and that is recorded for the nominal fill volume of each implant, that is the volume at the bottom of the manufacturer's recommended fill range for that implant. All saline implants have a range within which they can be filled, usually 50 cc. Thus a 400 cc implant can be filled to 400 cc, 419 cc, 445 cc, or anything else up to 450 cc, and so forth. Underfilling the implants, say putting only 380 cc into a 400 cc implant, or overfilling beyond the upper limit of the range, say putting 475 cc into a 400 - 450 cc implant, while sometimes done, is not advisable, and it voids the manufacturer's warranty on the implants. Having said that, when you fill an implant over its nominal fill volume, you not only change the volume, but you begin to alter the base dimension and projection height ever so slightly, and you begin to alter the tone, or firmness of the implant too. Thus, the overfilled implant begins to subtly become rounder, or more spherical than the normal discoid shape of a nominally filled implant, and it will become firmer, the more saline that is added, as well. Now, as long as you are within the recommended fill range you are safe, and this is no problem, but if you put an overfilled implant next to a nominally filled implant, you will likely be able to tell the difference. The implant that is overfilled will be tighter, firmer, project more, maybe noticeably narrower at the base (and thus appear "smaller"), and it will be less "sloshy," that is you may detect less motion of the saline and less of the interaction between the saline and the shell because everything is tighter. I expect that these are more the reasons behind what you are observing in your breasts.The answer to this is pretty straightforward, and it depends upon your preferences and priorities and your objective observations of your breasts. Sometimes we have to accept that there will always be some kind of asymmetry between breasts, and we just have to decide which we prefer. That is, would we rather have a slightly tighter, more projecting breast on one side in exchange for a better volume match, or do we prefer better dimensional symmetry, that is width, height, projection, in exchange for some residual volume discrepancy. This also includes the possibility of feeling a difference between the two breasts as one may be tighter or firmer than the other. Only you and your surgeon can decide this. Once you make that determination, the solution may be as easy as doing nothing, once you understand these things and accept things as they are now, or adding a bit more saline to the nominally filled implant, removing some saline from the overfilled implant, or changing to a different size implant on one side altogether to keep better dimensional relationships while not having to overfill either implant. In any event, these things are fine tuning of the result and not very complicated technically; they just require sound judgment, an artistic eye, and rational acceptance of the realities of what can and cannot be accomplished with our current technology. Good luck.
