We have tested it on several campaigns and found it to restrict advert delivery at hugely different multiples of actual spend.
We have one campaign set to 20 times the daily spend yet others set at just double.
I would test it by increasing your daily budget by 5x (as long as you don't have the ad optimiser on)
Raise your budgets dramatically for one day and test it.
I would test it by increasing your daily budget by 5x (as long as you don't have the ad optimiser on)
To the above advice I'd add this: never raise your daily budget higher than you are comfortable with paying, especially if your product or service is the sort of thing that might get unexpected and sudden media attention.
I'm reminded of the advertisers who advertised DeLorean parts, and who saw really substantial spikes with 'Back to the Future' appeared on TV. Please at least keep this advice in the back of your mind when raising your daily budget by large amounts. ;)
AWA