Iv actually considered removing all the free options from upwell structures, and just swapping them to better rates.
for example refine rates on null buildings do 70%, low 60%, and high 50%.
Same with repair
Null - 20% Cost, -10% low, 0% High
I bet a lot of isk would be recouped there, most of the isk comes from null anyways, so it makes sense to nerf that area more to balance what they put into the economy.