There is no work to save. You are constantly making attempts each of which has a very very small chance of producing a valid result.

Since even a solo cpu miner can perform millions of hash calculations per second losing a single calculation is insignificant.

The duration seems to be measuring time from 2 blocks back rather than 1. I wonder if slush had to split something into multiple threads and that is what is causing the problem.

Demonoid has a very good selection of audio books

If you received no rewards despite having your miner running at that time, it is mostly likely because you produced no proof of work during that period. Proof of work is successes at an artificially low difficulty. A block solution will also qualify as proof of work.

CPU miners are traffic inefficient because every client asks for work at the same interval (5 seconds by default for the one I use) but CPU miners do less work per work request. Thus they produce more traffic per khash.