first Posting from date not working for conditions with fixed rate option

Hi Team,

help me on how we can setup first posting date should work. my contract start date is 01.01.2016, but i want to post entries in system from 01.04.2016. when ever i am putting date first posting date as 01.04.2016. it is taking and saving, how ever it is posting entries from 01.01.2016 in RERAPP.