No, it is NOT. The difference is marked. The negligible bit is YOUR claim that the faster climb to Cruise Alt is the key. I argued against you, you typed like I defended your claim.
The post above also points you at Boeings website. It supports my argument, and my argument is based on feedback from ALL the Winglet operators. All those designed by APB that is.

My apologies for mis-stating your argument.

Furthermore, you are right. The wingletted airplane saves a significant amount of fuel even at the same flight level. Not satisfied with links to manufacturer websites, I have run that data on a fairly sophisticated flight planning system in use at a large airline. I was able to plug in a wingletted airplane and a non wingletted airplane. In one scenario I capped their altitudes at FL360, in the other scenario I let them climb to their most economic altitudes. The results are shown in the chart below, fuel burn in pounds for 4 hour 25 minute flight with exact same payload and winds: