Google Ads App Campaigns CPI or CPC

Last year i created a app install campaign for a tool app and it was getting installs from usa at £0.05 per install and I was getting decent volume at about 600 installs per day.
Its not great but it sort of maxed out and had to work within a budget.

I then stopped that campaign.

Then this year i sort of copied this same campaign for another similar app, so more or less same keywords and headings.

But now for £0.05 it will not even get 10 installs, let alone 600, so have to increase the CPI bid to £0.12 and even then its not even reaching 200 installs.,

Is there a reason for this. i dont think its the keywords or target countries, as both target mainly usa.

I would suggest that let google optimize the bidding, for example: set it to $0.40 and let it run for 48 hours and check your data. Check which GEO your app is getting most download from. Select broad GEO (whole country), put minimum filter, (Age,gender,demographics etc), you will have a better understanding and should see lower bidding over time. if it is working and your bid keeps coming down, let it run. DO NOT TOUCH it, google doesn't like it and your campaign goes back to learning more instead of crashing it mode.
Tip: if you're low on budget, use a threshold account, or new accounts where they offer coupons.
Hope this helps mate.