Sentence 1: However, the specific features and uses of IT differed significantly between and sometimes within the agencies.

Sentence 2: IT is a complicated matter, and using it effectively is difficult, that's where the differences came from.
Is this second sentence entailed by the first?

Answer: it is not possible to tell

Sentence 1: Sister is very sorry.

Sentence 2: Sister isn't sorry.
Is this second sentence entailed by the first?

Answer: no

Sentence 1: because that's another mystery and i don't have to concentrate too hard on them

Sentence 2: I really have to concentrate on the mysteries.
Is this second sentence entailed by the first?

Answer:
no