3-4 joseki question

[p2501]

The following occured in one of my games:

$$Bc
$$ ------------------
$$ | . . . . . . . . .
$$ | . . 5 . a . . . .
$$ | . . 4 1 . e b . .
$$ | . . 6 , . . . . .
$$ | . . . 2 . . . . .
$$ | . . . . c . . . .
$$ | . . 3 . d . . . .
$$ | . . . f . . . . .
$$ | . . . . . . . . .

Click Here To Show Diagram Code

[go]$$Bc
$$ ------------------
$$ | . . . . . . . . .
$$ | . . 5 . a . . . .
$$ | . . 4 1 . e b . .
$$ | . . 6 , . . . . .
$$ | . . . 2 . . . . .
$$ | . . . . c . . . .
$$ | . . 3 . d . . . .
$$ | . . . f . . . . .
$$ | . . . . . . . . .[/go]

a and b are two possible continueations for black. Since after b white could play d because the ladder favors him, black seemed to not want to play b. But if he would have played a, white could play c and look forward to either pressure the top with e or the left with f.

But black then played e himself:

$$Bc
$$ ------------------
$$ | . . . . . . . . .
$$ | . . X . . . . . .
$$ | . . O X . 1 . . .
$$ | . . O , . . . . .
$$ | . . . O . . . . .
$$ | . . . . a . . . .
$$ | . . X . b . . . .
$$ | . . . . . . . . .
$$ | . . . c . . . . .
$$ | . . d . . . . . .

Click Here To Show Diagram Code

[go]$$Bc
$$ ------------------
$$ | . . . . . . . . .
$$ | . . X . . . . . .
$$ | . . O X . 1 . . .
$$ | . . O , . . . . .
$$ | . . . O . . . . .
$$ | . . . . a . . . .
$$ | . . X . b . . . .
$$ | . . . . . . . . .
$$ | . . . c . . . . .
$$ | . . d . . . . . .[/go]

Now if white plays a, black can choose between b, c and d. Either way: How can white attack the top group in the following position(?):

$$Bc
$$ ------------------
$$ | . . . . . . . . .
$$ | . . X . . . . . .
$$ | . . O X . X . . .
$$ | . . O , . . . . .
$$ | . . . O . . . . .
$$ | . . . . O . . . .
$$ | . . X . . . . . .
$$ | . . . . . . . . .
$$ | . . . X . . . . .
$$ | . . . . . . . . .

Click Here To Show Diagram Code

[go]$$Bc
$$ ------------------
$$ | . . . . . . . . .
$$ | . . X . . . . . .
$$ | . . O X . X . . .
$$ | . . O , . . . . .
$$ | . . . O . . . . .
$$ | . . . . O . . . .
$$ | . . X . . . . . .
$$ | . . . . . . . . .
$$ | . . . X . . . . .
$$ | . . . . . . . . .[/go]

Seems hard to refute the deviation from the joseki at my level.
There is a pro game with a similar position, but in more than one way it is different:
http://eidogo.com/#2z4Nrt:0,29

[RobertJasiek]

B18 is a temporary attack on the upper side group. If Black defends the top, White attacks the left side.

[logan]

Yes, b18 is sente now and leaves Black's top group over concentrated. Black wishes stone were further out at B or he played A instead so b18 wasn't sente and could play a more efficient move such as g16. And like Robert said "If Black defends the top, White attacks the left side."