In almost all cases, Google does not display your ads every minute of every day when your keywords are searched for in the SERPs. This means that sometimes, when Nozzle pulls your SERP, there will be no ad data to collect.
We can only report SERP data that is present at the exact time that we extract the data.
To verify what our tool saw, drill down to the Single Keyword dashboard on any keyword for which you know you are paying for ads and then scroll down to the SERP visual (Nozzle Vision).
You then can see whether or not an ad was present when we extracted that particular SERP.
You can also select and analyze any date from the gray drop down right above the SERP visual.