Version galore... We make a lot of curves... we release some! I think I gave you a stick of curves at the workshop in Santa Fe and they are probably not release - could be different than release. Maybe you have downloaded the release since and you have multiple copies. Also we did not differentiate so much in the available documentation of the curves as we first began releasing them to Roy Harrington. And there just are different version sets...that I travel with - and who knows what I brought to Santa Fe!
So here is curve diagramed out...
"Max" is total percentage of ink of a particular shade (or color). Although I would never do it (because the ink will pool and run off the paper) if this is set to a value such as 65536, that would in theory allow that print channel to express as much ink out as it is possible for that ink channel to express - the 100% amount of ink.
The crossover points are where the curves intersect. They slope from off (left) to the right when looked at in QTR Curve preview on Mac OS. The ink begins in each curve at the furthest-most curve point to the left and as more density is required it moves up and to the right. When the ink begins to trail off the curve moves lower and continues to the right until it is 0% (off). In a Piezography curve, there is much blending because the curves have long tails. At 80% grayscale density you can see that 80% gray would be printed by:
.05% shade 6
40% shade 5
44% shade 4
40% shade 3
1.25% shade 2
80% is a particularly beautiful Piezography tone of gray, and one accumulated from 5 inks. So split-toning by ink channel takes a lot into consideration and is why we did some custom blending at the Santa Fe workshops.