It's not really contradictory, minor changes can have major effects.

So they meant a "small" update - "conservative", "inexpensive"...

An example when using a less frequent term actually reduces specificity.

Changing TREE(2) to TREE(3) is a small change on the input, but a... lets just call it big... change in the output.

No, they used minor correctly.

Will you also explain, or leave it like that?