Speaking of symbol (PMC). I think we also need a short symbol (such as BTC or Ð).
That makes the currency feel more as a currency.

I was thinking about uppercase pi (Π), but I can't find a short ALT code to easily type it.

So another option is Phi (φ), which can be typed as ALT+237
I like that letter because it kind of looks like both a P and and (upside down) M.

φ15
φ0.25
mφ67

What do you think?