Well, didn't have an official session earlier in the day (had errands, etc to run....) - but Delta was sitting "reading" a book - and saw the word UP in it, and was pretty excited because he saw it and knew it. He found it in some other ones too.
He had no problem remembering "C" (kuh) - played 1/2 of the blocks game to earn 6 more pennies, and then (after I played it with Echo) - I showed him "CUP" - and we played the ledge game.
With Echo, I kept it still to just U and P - she did the whole blocks game, and didn't have a big problem with the ledge game even though there were all those extra cards for Delta. If I can get some time with just her tomorrow, I may work with UP again with her.... It just seemed to confuse her before.