OP, your posting suggests the following:

1. You are a platinum. You reached this through completing the requirements of plat - probably 60K points for the year (unless you had a special promo or as many are getting free plat now). Plat applies to ALL PC hotels INCLUDING IC.

2. Completely separate from #1, you are also an Ambassador. You got that through either buying it (with points or $), or got it somehow as a freebie from PC (or some promo). As others have stated, Ambassador ONLY applies to IC's. So if you stay at a CP, CS, HI, or HIX they don't care that you are Ambassador or not, it's like telling them you are a Hilton Diamond.

However, AMB does automatically gives you Gold status for the other PC properties.

If you are a Royal Amb, you automatically are Plat for the other PC properties.

At IC's, the order of importance goes: RA->AMB->Plat

Despite many saying that Plat means nothing at PC esp IC, I ALWAYS got a suite at IC's as ONLY a PC Plat. Now that I've become RA I only know it's guaranteed (plus empty the minibar).