This came up in a different thread: Carbide create -extra characters to get 15 - (strange)
For an example of the difficulties in font handling / sizing, here are two characters from different fonts, set to the same ostensible point size in InDesign — notice that both are selected, and read as being “120 pts.”:
This is caused by the outlines for the fonts being placed differently on the “em square” used to design the fonts.
See: