How to keep original character space???

After I add a new character to a exist true type font set the space between character increased more than 5 times compared with original space. Please help me to keep original space.

Try Paste Special where you can choose from:

:arrow_right: Glyph Outline Data
:arrow_right: Glyph Metrics
:arrow_right: Glyph Postscript
:arrow_right: Glyph Mappings

Even just save a exist true font set without any changes, the space between character increased more than 5 times.

Do I need to change any setting??? Please help.

Here is the problem:
Before saved with Font Creator 5.0:

After saved with Font Creator 5.0: