Is this evaluation ok?
Does it have no correlation with about 32SC ~ 3min and 50BTC ~ 10min ?
Target time/block doesn't enter this calculation (it only affects what difficulty a network will end up at at a given hashrate).
Just block reward (thats where the 32 and 50 come from), difficulty and exchange rate.
another way to put per-block reward, difficulty and exchange rate together:
1 share on BTC gets you about 50/1806098 BTC = 0.000027684 btc/share
1 share on SC at a exchage rate of 0.0017btc/sc gets you ... 32/2703*0.0017 BTC = 0.000020126 btc/share
0.000020126 / 0.000027684 = 0.726990319 -> you're making about 27.3% less mining SC and selling em than mining BTC.
now... what exchange rate do we need to come out even?
50/1806098 = 32/2703*X
or...
X = (50 / 1806098) / (32 / 2703)
X = 0.002338432
you can also swap things around to suit you
X = (2703 / 32) / (1806098 / 50)
X = 2703 / 1806098 * 50 / 32
or replace the * 50 / 32 with * 1.5625
X = 1.5625 * 2703 / 1806098
... and it's still
X = 0.002338432
Wonders of arithmetic!