You said " (2) 2014 Mobil 1 AFE 0W-20 is the now all-time BOQI champion, easily beating the old, discontinued Pennzoil Ultra. The current formulation is still excellent. However, the base-oil quality of M1 AFE 0W-20 seems to be going down every year, meaning they are putting less and less PAO in it every year.".
I just bought a batch of PUP 0w-20 from Amazon, although yet to be delivered. On the Pennz website it is still listed as an active product. What product was discontinued ?
I have 12 jugs of the 5w20 PUP, I might have to consider sending them back....though base oil isnt everything, it is additives as well. Like you, I am a thin oil guy.
Oh, no!

The long-discontinued original Pennzoil Ultra, without Platinum and without PurePlus, was a PAO-based oil with incredible CCS and NOACK, with BOQI around 80, similar in quality to the PAO-based Amsoil Signature Series, current PAO-based Mobil 1 0W-20 formulations, and old, discontinued PAO-based Mobil 1 formulations for their thicker oils.
Pennzoil Ultra Platinum is a scam! It's not that it's a bad oil but it's actually inferior to Pennzoil Platinum and yet you are being charged twice as much.
Pennzoil Ultra Platinum 5W-20 (GTL-based) CCS,
NOACK, BOQI, price: 4050, 10.5,
47.0, $51.69
Pennzoil Platinum 5W-20 (GTL-based) CCS,
NOACK, BOQI, price: 4000, 8.6,
58.1, $31.90
Mobil 1 AFE 0W-20 (PAO-based) CCS, NOACK, BOQI, price: 4182, 10.7,
78.2, $22.88
Pennzoil Ultra Platinum 0W-20 (GTL-based):
high NOACK reported, mediocre/poor CCS (5670), therefore mediocre BOQI, yet super expensive
Take a quick look at the BOQI numbers and prices. Pennzoil Ultra Platinum is a good oil but it's significantly inferior to Pennzoil Platinum and vastly inferior to the PAO-based Mobil 1 AFE 0W-20 and yet vastly more expensive than both. It has an inferior base oil than that of Pennzoil Platinum but I see that they added some more boron additive in it to make it different. You have been scammed by a marketing gimmick, ripped off, and robbed. It's darn right that you should return them!