That would have been the case if they appealed for the points lost from the Hungarian Grand Prix and won it but they did not bother due to ending up losing all their points.
I hope that McLaren are not heavily underestimating the competition this year that they could be way off and aiming too low. Hamilton thinks they should at least be around the same position as last year, which is having the 2nd-3rd fastest car with developments coming for the first race but what if Red Bull were running more fuel and slower tyres on there faster runs and have even a better upgrade coming for the first race. The what ifs will go on until the first race is completed. The Bahrain cancellation should help McLaren the most out of the big teams to address reliability issues.
I think McLaren have been around long enough to know not to take the fastest times set in testing seriously. Considering that McLaren are worried and their drivers are not talking positive, I doubt they underestimate their rivals.
Why on earth would they think Red Bull can't go faster than they have in testing? Its very rare for any of the teams to go 100% for ultimate laptime in testing, McLaren themselves know this. I don't understand how you can think they might underestimate this.
The only teams that McLaren might underestimate are Renault, Williams, Toro Rosso and Sauber. Its quite possible they might fall by one or all of these. But predicting 3rd fastest car is not a positive statement from Hamilton, quite clearly they don't think the car is up to scratch.
Generally speaking, we learn more from the mood and comments from drivers and team personnel in testing than we ever do from the times. Last year, Mercedes were talking down their chances of championsips, which turned out to be true. In 2009 testing, teams were surprised by Brawn's fast pace which turned out to be true. This year we have McLaren and Mercedes sounding quite disappointed with themeselves, chances are they have fallen back this year.
Having said that, Bridgestone were raving about Sauber last year and that turned out to be a load of twaddle for the most part.