How much should I invest in an app campaign based on cost per order?

Here's the situation:

"Today is November 18th. We have been running a User Acquisition campaign for a Delivery App called “Delicious App” for the past 2,5 months.
The customer's main KPI is Cost Per Order. This is calculated as Spend (the amount invested by the customer) divided by the number of Orders generated by some app campaigns.
Some of the metrics we collected over these period are summarized in the following table:
View attachment 269892
How much do the advertiser plan to...

How much should I invest in an app campaign based on cost per order? WordPress ...