On page 298 GIPS EOC Q 4:

"For periods beginning on or after 1 January 2011, firms must not value portfolios:

A when objective, observable market prices are unavailable.

B. more frequently than required by the composite-specific valuation policy.

C. as of the last business day of the month unless it is the calendar month-end" Correct answer is B. how is this not allowed? It is good if they value it more than required-am I missing something here?

This point is explicitly in regulations. Just remember this and move on to other questions.