I don't know if this has been posted yet, but i just checked with Miliart, T.K. in Sandy at L-9 and he is the one that provides the new Sanction/Signet.
Tested it out on 1 fight and it does give increased exp (my friend got 17 exp with it on for an Easy Prey, while I recieved 13 exp from the kill). Estimating off 1 kill, thats a 25% bonus in Eastern Ronfaure (s).
Also, another cool thing about it is the additional refresh, regen, increased meal duration you could buy stacks. So theoretically you could buy all 3 if you wanted (they cost 50 Allied Notes each).