Hello Hayasaka,
Hope you're doing well.
I was checking your code and you are calculating your Cumulative value only in the Preparation.
And you are afecting your current's variable:
GetMainsBySmallShopId.List.Current.Cumulative
But when you execute your Search action, you only refresh your Aggregate and you don't calculate your cumulative values again. That's why they will be displayed as 0.
So you should add this exact same logic in your Search action, like:

Hope that this helps you!
Kind regards,
Rui Barradas