Samurai LB and frontlines

[Sinstrel]

thats prob what it is, well ill retract my statement. i coulda sworn it didn't take into count bh but it says on skill 100% of targets hp if applied.

Your BH also affects healing done which, ergo, increases your shielding done. There are very few jobs that don't have a shield and, of the jobs that do, there are fewer still that don't passively gain the shield as part of their standard rotation (as opposed to solely through limit break as in the case of DRG).