Question for future reports:
You for sure should use 'more frequent' pricing. It does not really matter which price you will chose to use, the important point it to use more current price . With 23% drop in price, using the same price for last Sunday's SD deposit as this Friday's Steem withdrawal can easily turn a net neutral 2 transfers from the same account into top 15 deposit/withdrawal in your list.
That's a good point. How frequent do you think it should be? Since the frequency graphs are daily, maybe an average price for the day on Poloniex? Things can even swing wildly within one day though. Maybe an hourly price would be ideal. I haven't really explored what pricing APIs are out there I can access for free, but if I had a simple way to say "get me the average price in USD terms of SBD and STEEM between 1pm and 2pm on date X" that would be ideal. Do you know of any services that provide that?
Polo prices are a free through ( I think pretty easy ) api. more info here . You can access them as often as you like. So 1h price are achievable and good enough 99% of the time, with not too much overhead, I think.
Nice! Hopefully I can carve off some time this weekend to improve my script before the next report.