well in hex 01 = 1 and 2c = 44. 44 + a tens place 1 would give 54, which is the number of levels you have cleared. However that does not explain why i have 0's and have cleared 11 floors.
That's because of an error in your calculation.
12C is 300,
lovely number 3E7 is 999,
max value 2-bytes, FFFF, is 65535,
max value 4-bytes, FFFFFFFF, is 4,294,967,295, same as max uint32.
05F5E0FF is 99,999,999, like in the save patches.
You don't add 'tens places' like pencil-and-paper decimal math. It's hex math, so there is a certain nuance in play. After 0-9 is A-F, (add 1 to next digit), and back to 0-9. Your result of 54 was a coincidence. The scope of the data type in question is 4-bytes, [0000012c] in the calculator, so I'd convert to decimal from there.