PPRuNe Forums - the difference proficiency check and competency check

I can't distinguish between the difference the instrument proficiency check and the instrument competency check.

In the ASA's 2014 Instrument Rating TEST PREP,

4021. how long does a pilot meet the recency og experience requirements for IFR flight after successfully completing an instrument competency check if no further IFR flights are made?

A- 90days

B - 6 calendar months

C - 12 calendar months

Answers is B, but I think C is correct.

Because

I think " 6 calendar months after completing currency, we enter the grace period for 6 calendar months.

after the grace period, we should complete the instrument proficiency check.

So after 12 calendar months from time currency is completed, we e should complete the instrument proficiency check. "

help me!!!