Can I get breast reduction to a point where it can give the appearance of a flat chest, or an AA cup?

If
you are a 38 C, it is not possible to go to a 32 AA.  The 38 is the circumference around your chest
at your inframammary fold.  That does not
change with a reduction.  The volume can
be decreased and change your cup size. 
If you have Poland syndrome, I would recommend reconstruction rather
than amputation of the breast.  The
reconstruction technique I recommend uses autogenous tissue used from the
abdomen.  You have the benefit of a tummy
tuck used to reconstruct your breast.  It
is possible to reduce the size of your other breast to make the reconstruction
easier to do and it may lift the opposite breast as well.  Unfortunately, you have not provided
photographs but this is an alternative for you.Best Wishes,Gary Horndeski, M.D.

I had a similar patient to you that we operated on last week.  A good procedure for patients such as yourself would be the Passot  breast reduction technique, assuming that you are a good candidate.  This technique leaves less scarring that the traditional "anchor" type scars.  I would recommend that you schedule a consultation with one or more board-certified plastic surgeons who can examine you in person and review your options with you.

Thank you for the question and congratulations on your decision to proceed with breast reduction surgery. You may be surprised to know that your goals/requests are not that unusual.   I see several patients every year who wish to achieve as small of a breast appearance outcome, for a variety of personal reasons.
 Generally speaking, it is possible to reduce the breasts size very significantly.  The concern with the amount of tissue removed is related to blood flow to the remaining tissue; if too much tissue is removed in one operation the blood flow to the remaining tissue (including nipple/areola) may be compromised. Part of the tissue that is left in place is called the “pedicle"; this segment of tissue is responsible for delivering the blood supply to the nipple/areola tissue. If the pedicle is made too small (in the effort to reduce the breasts as much as possible) then patient will likely have problems with tissue survival.   Occasionally, a staged procedure is helpful; in others, nipple/areola grafting is helpful.
 In my opinion, successful outcomes with  etc. surgery depend on:
1.  Careful selection of plastic surgeon (and from the surgeon's  standpoint, careful selection of patient).  I would suggest starting with the American Society of Plastic Surgery and/or the Aesthetic Society of Plastic Surgery to obtain a list of well experienced board-certified plastic surgeons. Then, I would suggest you visit a few surgeons whose practices concentrate on aesthetic surgery. ***Ask to see lots of examples of their work and preferably speak/see patients who have had similar procedures done.
2.  Careful communication of goals ( which I will discuss further below).
3.  Skillful execution of procedure ( preoperative, intraopererative, and postoperative patient management).
In my practice, I would ask that you NOT communicate your goals, or evaluate the outcome of the procedure performed, based on cup sizes.  There is simply too much variability when it comes to bra sizes between bra manufacturers and even store employees doing the bra fitting measurements.
 Generally speaking,  for the benefit of patients undergoing breast reduction surgery:  it will be very important to communicate your size goals with your surgeon. Most patients wish to achieve a enough of a reduction to help with their symptoms while remaining proportionate with the remainder of their torso. Again, I suggest that you do not communicate your goals in terms of achieving a specific cup size. For example, a “A cup” may mean different things to different people and therefore may be a source of miscommunication.
In my practice, I ask patients to communicate their goals with the help of  computer imaging and/or goal photographs,  as you have done here.  Obviously, the outcome associated with the breast surgery will not necessarily match that of goal photographs perfectly, but they do serve as a better communication tool that subjective terms such as "natural", "proportionate", "flat"… Evaluating goal photographs also allows for a plastic surgeon to determine the consistency of the patient's goals and allows for a discussion of realistic expectations as well.  
  Best wishes for an outcome that you will be very pleased with.