So, 1) even if you choose to mine w/ the same coin, your mining 'rewards' are still pegged to the amount of BTC those coins earned.  2) you are still charged the 5% exchange fee even if not 'exchanging' (b/c as I said in 1 you technically are).  No matter your payout coin it goes like this: reward > BTC > your payout coin.  The pool has a fee (2% for nist5) and the exchange to BTC has a fee (5%).  Which means you would pay 0.010108 in fees.  So .1444 -.010108 = 0.134292.  So you still have a difference of .00759636 when you factor in the static costs, which is 5% difference between expected and actual (far cry from 15% 'extra').  And when looking over the BWKs prices on the pay you posted on crypotia, there are more then enough greater then 5% prices swings downward to account for that.  Since most likely BWK has to be valued twice before you get your earnings, once when the pool exchanges for BTC and then again when it exchanges for your equivalent of BWK (BWK started out around 0.0007 then trended downward before finishing at 0.00063).  This is the main reason I get paid out in BTC,  and why I suspect that the non-btc payouts are 'use at your own risk.'

Nothing on here is more than conjecture and misleading information.  The 'evidence' is sp_'s screenshots, but they lack timestamps to validate and he is using polenex which I am pretty sure is not the exchange zpool uses for lbry.  But unless every auto-converting pool is also taking 20% zpool should show results that are lower than other pools.  When ran side by side (and assuming both pools have the same coins and other variables corrected for).  But the several side by sides that have been done and posted and the ones I did (when I do my next one I'll post results) show zpool either the same, very slightly below, above, or way above I just don't see it.