the formula for pci listed on the wiki site gives me a different pci value than the one i have on my advisor. i plugged in all the same stuff (tax-rate, net, land, ent, bus-tec, gvt-pci) from my advisor and the pci did not match.

is it out-dated or am i possibly doing something wrong?
22.5 * (1 - Taxrate) * (1 + ((Networth/Land)/90000)) * (1 + (2 * (Ent/Land))) * BusTech * GvtPCIBonus

pci changes, it grows and shrinks kind of like population does.

Correct. It doesn't immediately move to its equilibrium value
The equation you have is for the equilibrium value, not for the actual value. If you play a bunch of turns with that country, the PCI will move really close to that value, if not reach it.

When I did pci in a spreadsheet last reset it was correct.

I think I used a different forumla to that one though, it was a bit of a pain in the ass.