"Ad Network Installs" and "Attributed Installs" come from 2 different data sources:

Ad Network installs: from respective ad network

Attributed Installs: from MMP

Deviation between the 2 metrics could be due to the time interval of which both the data get sent through to Cost Center e.g. MMP data has arrived but not Ad Network data.

"Attributed Installs" is a more reliable metric as it is based on user level data while "Ad Network Installs" is just a number that the ad network reports.