I get why it's more consistent and I think it's the method I'll adopt with 70ml per roll in the first time.
But I don't think it's much more cost effective, it seems to be almost twice cheaper with my first workflow :
Adapt development times :
600/15 = 40 ml/roll
Replenishement :
70ml/roll
with your original workflow ( non replenished )
there might be problems down the road with bromide build up
( i think that is what it is, smarter people will know more cause i am admittedly clueless ! )
what happens is whatever it is that builds up streaks + messes with your film after a while,
replenishing is kind of like taking out the trash to keep everyting nice-nice.
after all, you have spent all the time finding stuff to dedicate to film ( photograph )
why give it the chance to get screwed up ?
to be honest ive never heard of using a developer like xtol non replenished, although i do use caffenol 130
non replenished, and i've gotten it to last for 5-6months but ... it starts to freak me out after a while so
i get rid of some of it and add new to the seasoned batch...
and i really don't use that developer except for "personal work" so that if it
is screwed up i don't care,
if it was for a client or friends or family ... i'd use something else.
they say replenished xtol is like manna from the heavens ... might not be worth messing with the manna
john
ps. dont' forget to have fun !