Alright.
It seems that you have a point and I have to apologize for being too stubborn to see it. Was late at night yesterday..
I'm not 100% sure yet how the rewards are really calculated - since there is no official statement about that - but it really bugs me when I do a mistake.
I've done 2 things now:
1.) Increased the basic factor to 2.75
2.) And made curation dynamic again. Meaning if the voter would get complete curation - then the factor is increased to 3.0.
Meaning:
You send 2 SBD - receive 6$ Upvote in the case of 25% curation.
I've also made an official statement about this!
https://steemit.com/steem/@smartsteem/quick-update-higher-upvote-ratio
Thank you for pointing this out!!
RE: Guide: Upvote-Calculation with SBD & STEEM for @smartmarket