The first one is a complete seki, i.e. if one player adds a move, he lose points (here, as almost always, he loses all his groups, but this is not the case in the following example).
But in the second position, White can get points by capturing the square block of 4 (first capturing the other 4 stones is a bad mistake, as White then loses everything!). When he next captures the other 4 stones, Black has no time to play back at the vital point (else she loses the semeai) and must be happy to get a seki: White scores 11 more points (by Japanese or Chinese rules).
Anon White gets 12 more points under Chinese rules, because white played one more stone than black.