All bent notes are "weaker" than non-bent notes because the reed is
vibrating a note that it wasn't built to sound, and it delivers less
amplitude because it's vibrating less efficiently.
Absent proof I'd say this doesn't match my experience. A quick check
with a dB meter and a G Marine Band yielded mixed results. Lower notes
with wider differences between the blow and draw seemed to be
appreciably louder when bent vs unbent. As I moved up the scale
initiating a bend definitely dropped the spl. Overblows were noticeably
lower in level but that says more about my ability to overblow than
anything else. I disregard this result because of my poor skills in
this area. In a bend reeds are forced to make sound at a pitch they
normally wouldn't sound at but it's not just the one reed. Unless
someone has already done the experiment I'd call the above a theory. fjm