I think the accrual time is something that the creator of the SMT determines when they launch the SMT - by setting some parameters. That's how I understand it but Im learning so I stand to be corrected.
I'm summarizing the white paper so you can follow me for my take. Here is the link to the first part. https://steemit.com/smt/@toni2oni/smt-whitepaper-summary-part-1
From the whitepaper page 41 I understand that quite a few parameters are fixed, like the reward accrual time.
Ahh ok. I see.