The Enchanted Grid

Sums become numbers digit by digit, but differences become numbers using something different

rawbatgas
napdadpan
sagtabwar


sum: ↗ = → = ↘ = ↓ = 1515

t=9, r=8

wn - bt = ?
ra - pt = ?
dg - ns = ?
gd - sa = ?
pg - gg = ?
ws - at = ?
np - wn = ?
pw - gp = ?
na - bb = ?