We are facing problems with an existing PEGA NBA application where NBA is used as decision as a service. Pega marketing version used is 7.1.x and per day approx 180K hits are made to NBA application which runs on 4 JVM nodes out of which 1 is a batch node.
When customer logs in automatically hit to PEGA NBA made to get the best offer(s) for him/her.

We are facing frequent timeout issues (if response time is > 2 sec timeout will occur). Following are the observations :

1) On weekends timeout % decreases as there is less customer traffic.
2) If the server is restarted, for a small period the timeout becomes less. But with time gradually timeout % increases.
3) If a particular customer has less number of rows in IH for him/her timeout % is less.

Can you please provide some suggestions and pointers for resolving / exploring this issue. Thank you.