When is the right execution? try this, you check the last 50 transactions in:
https://etherscan.io/tokentxns?a=0x8BBf4dD0f11B3a535660fD7fCB7158DaEBd3a17E

There is last time distribution information, you just add 10 minutes for the next execution. The time shown is GMT, so you have to adjust to your local time, use https://greenwichmeantime.com/timepiece/world-clock/custom/

See this picture.
https://cdn.pbrd.co/images/GRbPtFe.jpg