It isn't uncommon for the first couple of months to be 'spikey' in terms of lead flow as we gather data on which keywords are good performers vs bad performers and adjust bids accordingly. During that time, we're optimizing (making the right moves to get you the most for your budget).
Once we have that data, we can allocate budget to the best ad sources with the lowest CPL. (cost per lead).
Also even after this 'learning' phase, sometimes you may receive no leads for a few days at a time. This is just due to budget pacing. If the campaigns are over performing (pacing to spend more than your budget) they will get paused until it the system gets back on pace.
We try to keep it as smooth and as steady as possible but sometimes it can still get spikey due to changes in competition, seasonality, etc. Overall we try to get you the most leads at the best cost per lead within each of your billing cycles.
As the system gathers more and more data the flow will get smoother and smoother with the ultimate goal of delivering your total leads evenly as possible over a 30 day billing cycle.