Kitchen lights issues / solution

Ok so i have run about 7 meters of LED 50/50 strips around the kitchen and i seem to have a difference in power / light. i am aware of the drain that happens however being only 7 meters i think that should be plenty. only idea i have is to shorten the 2m strip that runs at the top of cabinets as its towards the end of that strip where it begins to get dim.

This is what i have used in the project


12V 6A 6 amp 72W DC POWER Supply

Not to change the subject but I do a large Christmas display using 5050 strips. To get a consistent color when jointing 2 or more strips power must be injected every 5m strip. I can not find a link off hand but looks like a T.
This is what we Christmas nuts use