Funny you should mention that,,, Mine does the exact same thing, but
it only happens at low powers settings like heading out to the active
while at taxi speed. Once airborne and making alot of power then the
readings are identical.

Ben
www.haaspowerair.com
Stan Prevost wrote:
I owned a turbo Saratoga with a Shadin, and have flown a lot in another
identical airplane with a Shadin. Work fine. One strange thing in both
airplanes is that turning on the electric boost fuel pump causes a decrease
in the fuel flow indicated on the Shadin, by anywhere from 0.1 to 1.0 gph.
We spent a lot of effort in removing elbows, insulating the transducer and
fuel lines, relocating things, never changed it.

I always thought it was weird.

Stan