My thanks to all who helped on this on and special thanks to Dico
Reijers for sending a F/F transducer for comparison.

I ran each transducer at RPM varying from 1700 down to idle and
recorded fuel flows.

The comparison transducer ran roughly 2.4 % higher at all readings
which leads me to believe that
the K factor varied  but the reading did compare.

If anyone with a TSIO 550E can give me their fuel flows varying from
1700 on down, I would appreciate it

Regards, Bill Hogarty

P.S. to Dico..  I'll be sending your transducer back to you this week.
I left connectors attached to the leads but you can
                      cut them off if you prefer.  Thanks again  Bill H.