Ledger Line confusion

[bitsybabe]

I am attempting to create a dynamic staff that adds ledger lines above or below the staff, as needed by the pitch.

I am using characters E010-E014 to represent 1 - 4 lines. The code I wrote was tested using E012, the 3 ledger line glyph, because that's roughly the maximum I'd use. The code places the glyph at a certain y-offset to the staff and adds +1 to the note's x-offset so it looks centered on the note.

Then I tested the 2-line glyph, E011. Instead of being at the same offset, it's at a completely different offset. In fact EACH of the ledger lines has a UNIQUE offset!

This is completely odd to me. WHY wouldn't you have kept the lines in the same place as you add them? They are the same distance apart, why could they not be the same position in the glyph frame?

I'm sure if Steinberg is using this font, there must be a better way to add ledger lines than what I thought: determine the offset and just change the glyph as the pitch rises or falls. Now, it looks like I not only have to change the glyph, but its offset! No bueno. WHY? Shouldn't glyphs in a font all have a common baseline?

Can someone please explain to me why this is awesome?