H.264 level >=6 in CC2018?

[NoMagnolia]

I'm trying to output some content which has to be 5328 x 912 in H.264 format. Reading up on the specs, this kind of resolution only seems possible at Level 6 or above:

H.264/MPEG-4 AVC - Wikipedia

But Media Encoder doesn't offer anything above 5.2. Am I doing something wrong here?

I'm on Windows using CC2018, Media Encoder 12.1 build 171.

[NoMagnolia]

I've got around this problem by outputting to uncompressed AVI, then transcoding that to ProRes using ffmpeg. But it would be good to find a solution to this that doesn't require mucking about on the command line.