how phloem give priority for transport sugar to buds

hello I have a question just by curiousity ,
when phloem transport sugars and proteins in the plant by the leaves to the buds , the buds will have competition for get the sugar , the question is does the buds that are near the most leaves that product sugar ( exposed to light ) will have high concentration of sugars and other buds near the leaves that are in the shade will not get enough sugar ,
i know that the upper bud have priority for intake sugar because its leaves in up are most exposed to light and because it will attract pollen in plant genetic it give priority , but the next parts how phloem give the priority for which bud get the most sugar because phloem move every where in plant not in one direction , does its concentration decrease , because in some plant there is difference in fruit size even two exposed to light and some dont grow at all.

You need to think of the plant as a whole, not buds. There's no discrimination in plant growth. It grows together at a certain maximum rate, or it doesn't because of nuances in the growing environment.
You grow a plant to its maximum genetic potential, or you come as close as possible. Basically, the more photosynthesis it gets, all things optimal, the better the plant grows as a whole, top to bottom.