ApexPC: Yep, the white numbers are essentially useless, since they only show the +/- distance to the middle depth of the green.
+1!
BPB #15 has an extreme slope but is it 16+16 (of which unit? yds? ft? inches?)? No, it's 6 ft = 72 inches.
One rather flat example is BPB#2. It shows +15 / 30 /-15, and the total slope from front to back is about 14 in.
Thus, the numbers in question point to the green center and are of not much worth without knowing the pin positions. But, different to reality, we get the pin distances by default, no need to calculate from green center or front of the green.