I was poking around chocorpg.ff8 with a hex editor and Hyne at the same time, altering things and seeing what changed. I found out that, at least on my save - and I've restarted Chocobo world a number of times to confirm this - Current and Max HP are read as the hex values - ie, 18 as a hex value, despite working out to 24 in decimal, is read by Chocobo World and interpreted as 18 HP!
Also, the item counts for Class A and Class B items when I have no items at all in those slots are 17 and 130, respectively. I have searched in my hex file and either not found those values in either hex or dec, or when I did, altering them either broke the save or did nothing. At one point I had found the hex value for Class D items, marked it in my hexeditor and everything. And that used the hex values as well, same as the HP field - 63 in hex, which should have been 99 Class D items, was instead 63 Class D items. But when I came back to it later, after several saves of the game in the emulated Pocketstation, as I attempted to locate some Class A-C items to be able to search for them in the editor, that marked hex location was no longer the relevant one for Class D items. In fact, I have been unable to locate the Class D item hex value again, even after editing each 00 value to 63, one after another. I suspect the location of the Item hex values, as well as what they consider their '0' value, changes as saves are laid down. That's the only explanation I have. But take that with a grain of salt, as I noticed that well after midnight, so when more well-rested I may find the appropriate hex entry.
But I do know that Current and Max HP, as well as at least Class D items, are read naively from hex instead of being properly converted to a decimal. Why the programmers did this back in '98 is beyond me, as it sacrifices all the advantages of hex for storing large numbers, and in fact makes the numbers take up significantly more bits for each value - as well, they had to write the code so it would skip over 0A to 0F, 1A to 1F, and so on. Entering a proper hex value for the appropriate amount of HP actually causes the HP counter to display the hex, rather than any reasonable HP value. I have not tested taking Boko into battle with an invalid HP count, but I can if it would be helpful.
. Everything work fine, only Chocobo World doesn't work for me X_X.