I'm ever so briefly out of the lurking shadows to share how I usually
answer this kind of Ezzo mom (and I have seen my share). I learned a
long time ago (10 years now I've been working with Ezzo parents) that
these moms are not offended by a suggestion of ABM, as they gain a
certain philosophical resignation in class beforehand if they need to
resort to it. I have called more than one peds to tell him/her not to
bother with trying to "rescue" breastfeeding, but to simply let
after-feed supplementation begin the weaning process - once we add in
the ABM the baby starts to gain, is far more content ( nay, even full &
satisfied) and is actually able to stay "on schedule."

Pertinent points (rearranged) of the provoking posting were [my
commentary in brackets]--
1) 3 1/2 month old [birth weight?]
2)  gained 12 ounces in 6 weeks.....[never mind - at any birth weight
this is dreadful]
3) down to 4, only four feeds a day, at 8a, 12p, 4p and 8p [and why not,
I ask?! :-/ ).
4) (She was very hesitant to add additional feeds because) she liked the
routine of her day [she is *not* "her kid's mom", even if she is staying
at home, because she is putting herself first over her *young* baby's
needs]
5) even though she had called with the question of how to increase her
supply (She said she knew I recommended on demand feeding, but) was
there any other way....? [read on]

"Yes. You must immediately start supplementing with artificial baby milk
[and I do use the words "artificial baby milk" - a little guilt is
healthy because this kind is motivational] since you have made the
decision not to increase the numbers of feedings in a day. It is *the
only way* that baby can gain well, under the limitations of 4 feeds,
spaced so far apart. Your baby should have been  gaining 1-2 ounces *per
day* for the past 3 months [and I plot out, on a real growth chart, her
baby's life to date, and I leave it with her - nothing like a picture to
drive home the point] for optimal brain development. This brain
development fortunately continues through the second year so no harm has
been done - yet. [After all, we don't know everything about brain
development, but I firmly believe that this is critical information mom
must have in order to make a legally-defined "informed choice" BTW, I do
check the head circumference on a baby like this to reassure mom and
myself and the peds that head development is still on-curve - usually it
is, even though weight/height are fallen off-curve] In fact, Gary and
Ann Marie would be the first to tell you that your baby is in the
particular "context" of slow weight gain [I point to the growth chart
again] and you must *parent to that context* [these are key words to
use]. In fact, they would probably say you have cut out too many
feedings too fast and should add back in at least two per day. [I would
check here that she is using the most recent materials, as they are
getting a little more flexible with each successive edition] You can
stick with your routine if you like, but to make that routine *safe* [I
emphasize the  word] for baby's growth, you must supplement with at
least 2 ounces of artifical baby milk after each of the 4 breast
feedings. Then you can have the best of both worlds."  :-)

Believe it or not, this will not cause the reaction you'd think - the
moms take to the suggestion with great aplomb, and baby starts to gain.
Mom of course, starts to wean, but she already has started weaning
already anyway.

BTW, I'll lay dollars to donuts this baby is clinically depressed and
somewhat withdrawn (has already learned that the world does not come
when needed, so no longer cries when there are needs), yes? I've seen it
too many times. This is the one time ABM is a blessing - once baby
starts to get filled up at a feeding and gain weight, their depression
lifts.

Lest I sound too sarcastic, let me share some observations and
philosophical musings. This particular kind of situation always bothers
me, but I don't personalize it anymore. This is her baby and she has
asked me how can I help her be the kind of parent she wants to be. My
job is to help her succeed within *her* definition(s), but in a manner
that is medically safe for both her and her baby. If that means adding
ABM, so be it. At least she trusts me enough to ask me! And I want her
to keep trusting me to keep asking me.

One thing I learned over the years is that, without exception, Ezzo
parents have set high goals for themselves as parents, their babies are
highly desired babies, and last, but probably first and foremost, God is
a welcome guest in these homes. I have been fortunate to see many of
these babies grow up (at least to 10 years old!) and they are fine,
well-behaved (not Stepford kids either!) happy, bright, confident
children. Even the several with Down's and the one who had part of the
brain removed as an infant following an accident and the surviving 24
weekers with brain-bleeds - are fine, well-behaved, happy, bright
children and a pleasure to be around. It is probably because I have had
the privelege of seeing some long-term outcome that I finely settled
down about the whole thing. My personal belief is that, because God is
present in these homes, God more than makes up for any inadequacies
suffered in infancy surrounding feeding. The parents shower love and
attention on their little ones, but differently than you or I would. I
guess that God's presence allows the parents to be (as Bettleheim said)
"good enough parents." That all parents should be so lucky...