Admob having less ad requests and impressions using applovin mediation

Question

I am using applovin mediation and using facebook audience network and admob to show impressions. The problem i am getting is that i am getting decent requests and impressions from facebook audience and applovin but getting very low ad requests and impressions from admob showing on applovin dashboard. All though my admob account is not effected by ad limitation. All i can assume is the value which applovin asks for admob placements ids i.e CPM value. I have set it to 1$ and set same to the admob account in global CPM tab. I am using interstitial only for admob. I tried changing this value to less than 1$ but getting same result. What i learned so far that this is the minimum value for ad serving means if i set this to 1$ then admob will serve ads greater than 1$ CPM but i get the static value always in the eCPM tab in applovin for admob and i.e 1$ , means that only ads with 1$ CPM are showing and not the above ones. I have connected my applovin account with admob in the networks tab. What could be the reason behind it?