It looks like, due to Hive's price, my balance of HSBI rewards has been running a little bit low recently. Indeed, I've also been posting more frequently lately, hence I've run through this balance rather quickly.
It appears that even 
This is an expected effect, as the balance noted above is in dollars; thus, when Hive's price increases, each HSBI unit becomes more expensive. It takes more HSBI units to get the same % vote from all the HSBI accounts. The reward is higher in dollar amount, but approximately equivalent in $HIVE amount, if that makes sense.
Thus, I'm going to have to come up with some ways to increase my HSBI. I've already been thinking about opening a community (to be moderated and run by some people I know) for which I can create an account and fund it with some HSBI units, thus increasing both my HSBI and the new account's HSBI. I've also considered creating a contest on the FC community, specific to my interests, that I can run on a schedule that I can follow.
I might end up going through with both of these. The community would require some building, especially initially, but I should be able to easily let go of it, as it's not as structurally complex as what I had planned for FC. The contest is also easy to uphold as long as I establish rules that make it easy for me to access submissions on my own time.
Nothing official here in this post, but I think I'll get those ideas rolling sooner than later.
One other thing... changing my post rewards to 50% HBD and 50% HP. That way I can convert the HBD to HIVE and use that for more HSBI rewards. This will be simpler than sending these into Hive Engine and dealing with 2nd layer stuff, which I'm gradually trying to reduce for the sake of quality of life.