It's not the 3.5, it's the Taurus engine layout. Without cooling the intake with METH, or going E30 (if the fuel pump pressure is 'ok') you are going to see much slower numbers once things get hotter. Mine would loose as much as .4 tenths at PIR at 105f before i went meth.
The engine is a stout mofo, change turbos, HF-cats, 110 octane or meth spray and these engines make north of 700FTlbs easy.
Your 2.1 60' really says you have a elevation problem 1st, and a tune/heat problem second.
when i traveled to 4500ft elevation my tune from 200ft absolutely sucked. (not your fault AJP, roadtrip) so my spooling took MUCH longer to occur.
Here is my thought and 2c. if you live way up there at 6000+ feet, you have a double wammy. your thin on air to start with, so spooling will be slower but when it gets hot, you go thinner on the air yet. your engine control will pull butloads of timing to compensate for AFR and SAFETY.
now one thing i will say, Torco is a bad idea stop using that. if you are tuned for 92 octane\93 octane you are tuned for a specific flame front. adding a bunch of flame retardant will cause your fuel to burn SLOWER and reduce spark>TQ.
I get adding to prevent knock, but unless you run 2-3 runs and see +3 or more KNOCK on launch or in the run in multiple places, you don't need fuel adders messing with your burn rates and slowing you down.
all in all i think you ran slow because of thin air brought on by elevation AND heat, and the Torco.
IF it were me, i'd hit my tuner up for 2 pr three tunes at that elevation
-Under 80f tune
-over 80f tune
-winter tune, at that elevation you get snow and ice and AWD cant stop 600lbfts TQ trying to kill you.
Regards!