Becky,
A lactating colleague did some simultaneous side-by-side testing of lite vs
Lact-e, measuring the amount of milk obtained while pumping with one on the
left and one on the right, then switching.  She consistently got more milk
with the heavier pump.  Can a mom psychologically control one breast apart
from the other?  Hormonally and neurologically, I think not.
        We have to be really vigilant about not uncritically accepting studies
performed by commercial interests on their own products.  I have been unhappy
with some of the marketing ethics of certain breastfeeding products companies
recently. Sometimes our clients' interests dovetail with those of pump
companies, other times they do not.  It's a crime that the third party payors
in your area will not cover the classic.  If it is illegal for an insurer to
insist on a generic drug against the physician's orders, how can they insist
on an inappropriate pump against our clinical judgement?
Arrgh!
Catherine Watson Genna, IBCLC