Very interesting comparison video.
Yes, F2012 is cca 50km/h slower on finish line.
But in this video we can also see that F2012 lacks speed in first three turns also.
But after that, as far as I can see, generaly on every straight Lotus reaches higher top speed, but every turn, and every apex, Fernando has at least 10+ km/h (one turn I noticed 30+ km/h) speed advantage.
For comparison purposes (minimum speed trough turns unless its apex):
Turn 1: Lotus 136 - Ferrari 126 - Williams 130
Turn 2 apex: Lotus 180 - Ferrari 152 - Williams 181
Turn 3 apex: Lotus 232 - Ferrari 203 - Williams 230
Turn 4 brake point: Lotus 290 - Ferrari 280 - Williams 291
Turn 5: Lotus 95 - Ferrari 103 - Williams 97
Turn 7 brake point: Lotus 267 - Ferrari 269 - Williams 266
Turn 7-8: Lotus 138 - Ferrari 170 - Williams 136 (F2012 never drops under 170 in these 2 turns)
Turn 9: Lotus 219 - Ferrari 230 - Williams 219
Turn 9 exit: Lotus 230 - Ferrari 245 - Williams 234
Turn 10 brake point: Lotus 297 - Ferrari 290 - Williams 295
Turn 10: Lotus 72 - Ferrari 91 - Williams 75
Turn 11 apex: Lotus 180 - Ferrari 176 - Williams 189
Turn 12: Lotus 113 - Ferrari 160 - Williams 111
Turn 13: Lotus 129 - Ferrari 130 - Williams 127
Turn 14: Lotus 84 - Ferrari 80 - Williams 85
Turn 15 apex: Lotus 100 - Ferrari 98 - Williams 96
Turn 16 apex: Lotus 213 - Ferrari 162 - Williams 219
Finish line: Lotus 280 - Ferrari 230 - Williams 275
Too bad we dont have Q3 laps to compare, in this video Kimi has better lap then Fernando.
Also, to me is kind of obvious that Lotus has different setup with less DF, reaches speed more rapidly but has less speed trough turns. Considering that, its hard to compare traction levels in this video.
* ofc we dont know where Fernando used KERS
** feel free to correct me any time
EDIT: added Maldonado
*** pretty much has no use to compare like this but oh well,...