My perspective is a bit different.
Optimizing every sale of a graded card should involve using ROI (return on investment) as the standard for that card, and not whatever a PSA benchmark is.
Over the years I have tracked my personal ROI for all three grading companies, and perhaps surprising to some the ROI I have realized from all three is essentially the same.
PSA cards cost more and sell for more because of the Registry, a successful marketing tool indeed.
But if I can buy company As card for $50, company Bs card for $60 and company Cs card for $80, and ultimately sell them for 30% more at $65 for the A card, $78 for the B card and $104 for card, I make 30% regardless of the letters on the slab.
With this approach and my experience, I consider price when purchasing but have minimal concern about which slab the card is in. "What difference does it make anyway?"
Please note well that I am a collector and not a dealer, holding cards I sell for an average of five years. I could care less about the Registry game or Registry prices. The crossover game for profit is a casino that I don't frequent. In my current collection All three grading companies are represented by at least a 20% share.
I have the data to justify this approach and opinion and I am only crazy 37% of the time. Those who disagree may be.