Elite visa help please

Hello all,
My boyfriend applied for the 5 years Elite visa back in 2014 and it will expire end of May this year.
We are keeping our options open and maybe go for the 20 years at 1 million.
However, I read that because you are supposed to get one year extension every time you get back in Thailand, it might be possible to get an extra 6th year of visa if you leave and come back before the visa is expired (provided you then stay in Thailand for a year). Can anyone here confirm if that is actually the case or if they will put the date in the visa as the deadline to leave the country (no 6th year)?
I would really love to have some help on the matter as one year free visa would not be a bad thing!
I apologize if my English is not perfect, I tried my best 😉
Thank you!