I've just got one of these and it is really annoying but I've found a workaround for this problem.
If you always crank at the same wattage (like I do) and have no reason to change it, there's a nice way around the problem.
You have the option to change ALL of the memory settings to the same wattage so no matter how many times you press the up and down buttons while unlocked, all it does it change the memory setting and not the wattage.
So to change the memory settings, click the fire button 3 times in quick succession, go to mode, scroll to memory, change the strength (soft, medium, hard), and then there's 22 memory settings. You can change ALL of these to the same wattage.
Now when you're on your normal screen, in the bottom left it should say MODE and then M1, M2, M3 etc... and you'll notice that when you press +/- while unlocked, all it does is change the memory setting and not the wattage, and because all your memory settings are the same, it won't change the wattage.
If you want different wattages, and want to change on command, then I guess you're S#!t out of luck though.
Hope this helps.