You’ve completely mixed up CRF with QP encoding which is what you are describing. Two different x264 settings can drastically change output bit rate of two same CRF encodes. Also, what the hell does MPEG2 or MVC have to do with x264 encoding? You’re still reaching instead of providing actual information rather than anecdotes.

The settings used on the current 1080p essentially neuter the release. Even scene groups are required to use better quality presets these days. The motion estimation settings alone cause a huge amount of grain shift from frame to frame. There is so much more to x264 encoding than CRF values and bit rate. I already contacted TM-1 with baseline settings that would dramatically improve their video quality. I just hope they use them.

Edit: and don’t use --tune grain!! That preset is almost as old as x264 itself. It uses far too high values of --psy-rd and will introduce artifacting and increase bit rate requirements. It’s more of an artificial sharpening mechanism than anything else.