Why does the widget show an older number than the app?
The phone refreshes widgets on a budget. Opening the app refreshes them immediately; so does "Refresh now" in the gallery.
From the guide Home Screen Widgets (iOS & Android).
How often it refreshes
Widgets refresh on their own roughly every half hour, and every time you open the app, sign in, or pay something. The phone decides the exact moment; iOS and Android both budget widget refreshes to protect battery, so a widget can be a few minutes behind the app. Each widget shows when it was last updated, and a widget that could not reach Seayora keeps showing the last good numbers with a "couldn't refresh" note rather than zeros.
Read the whole guide: Home Screen Widgets (iOS & Android)