You're inventing scenarios that simply won't exist in any large number.
The value of PC can be calculated by anyone with a simple knowledge of algebra. My editorial even gave the equations. The numbers may have been slightly wrong, but I even stated that, and that it was the equations that mattered.
If PC has high profit: You have a Mothership with 200 energy. It takes 50 to cast PC, and 25 to Wormhole. You have 3 bases. You cast on your first base, wormhole, cast on second, wormhole, cast on third. By that time you have 0 energy left. All you can do is hope your energy recharges fast enough for you to keep a constant PC going on your Probes, seeing as you won't have ebergy for abilities.
If PC has low profit: You have a Mothership with 200 energy. You might cast PC once as you wait for your army to Warp-In. Then you'll attack with 150 energy to cast spells. Then you'll retreat, and maybe cast PC as you rebuild your army and if you have nothing better to do.
Its sad when the only time PC gives you choice is when its so weak its hardly worth even having it exist.