I have done ligature substitution with the help of this doc. Once done, I have reduced the height Element > Transformations > Glyph Origin > Scale Uniformily ... with for reference.
Finally I have generated the font file. Using that I have rendered in HTML, there is a height difference in the characters of the font example1: size 10pt but for size 12 pt it is properly displaying, similarly example2: size 10pt also size 14 pt I can see difference.
How to fix this?
I have tried by changing the emsizes. I think the issue might be in kerning.