Thanks Brad and Mclandy, I understand now.
As Brad says, I need to plan ahead and employ a bit of 'lateral thinking'.
I've now got the song titles displaying on the L1 tones which is what I wanted, albeit that the tone number doesn't match the setlist. To put the icing on the cake, as Mclandy says, sometime in the future I need to start from scratch and think carefully which status (U1 or L1) I need to register first, so that the songs displayed increase in strict order, 801 Song A, 802, 803 etc.
Thanks again for the invaluable help!