ttc format converting err...

I’m trying to modify existing ttc format file.
In case of single type font, it works. But in case of multiple type containing font, for example ms gothic & ms ui gothic at one msgothic_1_80.ttc, there seems to be error happened.
when i opened the msgothic_1_80.ttc file at font creator 5.6, there was created 3 ttf files. But every files didn’t contain all font characters. And the omitted characters were not included at any of the new created files!
In case of containing multiple type font at one single ttc file, font creator 5.6 seems to work incorrectly.
Is there any fault with me?

If the characters are not in any of the three TrueType fonts, it means they are not included in the TrueType font Collection (TTC). You can add missing characters with FontCreator, but you need other tools to combine them into a single TTC.