Please read that post with caution, it's a very old one and was written while I was still figuring things out.
The APR % on SBD is currently set to 0. This is a setting the witnesses control. If SBD goes below $1, that number will go up. Right now SBD is well above $1 in value.
I pointed out the 0% in the previous post! Again, this was to illustrate that the function is present.