Reply #18: Let's see

[ProSense]

potential for Dems:

CA Fiorina (R) 47, Boxer (D) 45 (win)
CO Buck (R) 48, Bennet (D) 39
FL Rubio (R) 36, Crist (I) 34, Meek (D) 15 (seat currently held by a Republican)
IL Giannoulias (D) 40, Kirk (R) 39 (win)
KY Paul (R) 43, Conway (D) 43 (could win, loss of a Republican seat)
MO Blunt (R) 48, Carnahan (D) 43 (could win, loss of a Republican seat)
NV Angle (R) 48, Reid (D) 41 (win)
OH Portman (R) 43, Fisher (D) 39 (seat currently held by a Republican)
PA Toomey (R) 45, Sestak (D) 39 (could win)
WA Murray (D) 47, Rossi (R) 47 (win)
WI Feingold (D) 45, Johnson (R) 43 (win)

I'm not understanding his math because four of those seats are currently held by Republicans.

So if Dems win those three of those four seats, they break even if three incumbent Dems lose. If Dems fail to pick up those seats and lose three incumbent seats, they come out ahead 55 to 45. If Dems lose seven seats and fail to pick up any of the four currently held by Republicans, they come out 51 to 49.

Am I missing something?