You misunderstand. Bob sees his own clock tick off four years ( from year 0 to year 4 ) on the way out and four years ( from year 4 to year 8 ) on the way back.

Bob sees Ann clock tick off 3.2 years ( from year 0 to year 3.2 ) on the way out and 3.2 years ( from year 6.8 to year 10 ) on the way back.

3.2 - 0 = 3.2

10 - 6.8 = 3.2

3.2 + 3.2 = 6.4

3.2 / 4 = .8

6.4 / 8 = .8

Bob sees his own clock ticking off 8 years on the whole trip, and he sees Ann's clock ticking off 6.4 years on the whole trip, but Ann's clock jumps at turn-around.

Sometimes you win, sometimes you learn