That was a good part number. In reviewing the impedance specifications with Airmar your R-155 should be OK with using a "B" tap on 50Khz and "A" tap on 200Khz. However this transducer has never be tested with the FCV-295 so it is unknown how it will perform.
Thanks for the additional information. However the fact remains that the R-155 that you have has not be tested with any Furuno sounder. With the part number you supplied we have an idea of what the impendence should be. Using a BBFF3 with transducer with those impendence values equals using Tap setting of "A" on both frequencies.