Well, there is more than one type of AR cheat to begin with. There are AR1, AR2, and AR3 versions for the cheat format. I'm not 100% sure, but your simple conversion method doesn't look right to me. CHT format codes look like this:
ON=00E9C,27,0F
or this
ON=0118C,00,98,96,7F
Your's look more like NDS codes to me, maybe I'm mistake here.
There is a conversion method
HERE which has worked for me 50% of the time which you can read through if you'd like.
CycloDS also uses .CHT files according to my research. Their rom patcher grabs them from a folder automatically and patches them to the rom file (very similar to the G6 Lite's method) so they have to be renamed back to only the release number again (ex. "0001.cht", etc).
BTW - your link to download emucheat is bad, I can't get the file from that link. I tried searching for a copy of emucheat elsewhere, but none of the versions I found had anything to do with GBA cheat, only dreamcast and N64, etc.