Requirements for Thryus Meld??

I have two Grade Three Quicktongue Materia, and the Madman Whispering Rod.
When I requested meld from level 50 weaver, it wouldn't let me, says it will use higher grade carbonized matter than necessary, (level 5 carbonized matter) then it says it will be successful with Alchemist. I thought it could be any DoH?
What's the deal? Do I have to buy lower level carbonized matter...?
Please help!

No, only an ALC can meld that for you.

When it says it will use a higher grade than necessary, you can still do it. It's just letting you know that since you don't have any of the required grade.

Ok thank you !