i feel you and i could see where you're coming from, but what i've seen and read, 2 easy basically summed it up all in a nut shell.
Boron is important when dealing with maturation, pollen germination and seed production. As well as keeping calcium in soluble forms and keeping the stems, stalks, branches strong. Born keeps good colour on the leaves and helps produce the plants structure. Boron also aids in cell division and protein formation.
Boron deficiencies will show up first in younger leaves (they may turn yellow), then moves up the plant. Boron deficiency can resemble calcium deficiency. Stunting, discolouration, possible death of the growing tips, bud abortion and development. The Roots will show a stunted with swollen short secondary roots, leaves distorted, sometimes bronzed or scorched. Tip of the shoot dies; stems and petioles are brittle. Boron deficiency plants are easy to tell, because of the spotting the leaves show like a strawberry mark and or splashes of the marking. Boron-deficiency symptoms first appear at the growing points. They also can show signs of newer growths turning gray and or dying, bud deformed, curling of the leaves which are often spotted and discoloured. Newer growths appear to look like they are burnt. They can show signs of hollow stems along with yellowish to brownish colour leaves. Dead (Necrotic) spots develop between leaf veins, as well as the leaves becoming thick. The leaves will wilt with necrotic and chlorotic spotting. Boron is poorly absorbed with low potassium content. First signs of the deficiency are abnormal growth tips. Having not enough boron can also invite troubles for fungus problems from the internal tissues to rot away, as well as the root hairs along with them being discoulored. To avoid having a Boron deficiency try to keep the ph below 7 and to improve the moisture as well as retaining light soils.
Too much boron in your plants can produce a lot of problems. The leave tips turn yellow progressing inwards causing the plant to soon die slowly along with leaves dropping a lot.
Can show same signs as if a magnesium deficiency, but only happens on newer growths. Parts affected by a boron deficiency are: Growing points and young leaves.
as you can see the new growth is growing normally, none looks to be gray or dying. buds don't look to be deformed. best bet is to flush and take from there.