Enchanter research

[Pyrion]

I have a problem with research. When i dinged 16 i went to my trainer and got the research skill which immediately got up to 16, as is usual. I wanted to train more, but got the message that i am at maximum already. No biggie i thought, will come back later. Now at 18 i still can not increase my skill. I did 2 combines already (one successfull, one not) and dont get a skill update either. Is the skill max for Level 18 still 16? When does it go up? I dont understand this and could not find infos about it, please enlighten me if you know better.