User self-service sheet subscriptions should have an "upon app reload" delivery timing just like in the Alerts feature. The strictly time based approach is very limited. The data could be stale or to avoid stale data the subscription has to come so late to not be timely or useful.
I agree with this, it would be great to send out a subscription via email when the app reloads. The time based approach means there's a risk of stale data being emailed.
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