HPACK opcode bit patterns

1) 1xxxxxxx: "Indexed Header Field Representation"
2) 01xxxxxx: "Literal Header Field With Incremental Indexing"
3) 001xxxxx: "Maximum Header Table Size Change"
4) 0001xxxx: "Literal Header Field Never Indexed"
5) 0000xxxx: "Literal Header Field Without Indexing"

Do we really expect tablesize (3) to be more common than literal_without_indexing (5)?

I don't have a strong opinion to change the masks, but I am curious if the bit pattern selection was deliberate.