GIPS Input requirement versus recommendation valuation, business, calendar, starting, include

lxwarr30

Standard 1.A.4 states that starting 1/1/2010, firms MUST value portfolios as of calendar month-end or last business day of the month. However, one of the recommendations (Standard 1.B.3) states, calendar month-end valuation or valuation on the last business day is recommended.
So, what is the point of requiring then only to include as part of recommendation? Any thoughts?

sameeragarwal

This means that before 1/1/2010, its not required yet, but recommended.
After 1/1/2010, its required.

IAmNeil

Is this the 2010 version of GIPS? This would make sense if it were the previous version.