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I was wondering if I have potentially increased the cylinder pressures enough at 60-80MPH for the computer to pull timing?
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Welcome to [FJ]focaljet.
That's a "Randy from FocusSport" question... depending on the drop in ambient air at 70 MPH, your iat's will drop meaning the engine is inhaling denser air and therefore there'd be a slight increase in cylinder pressure...
The differences in the spark timing changes' effective torque you feel are more than likely a result of the spark tables associated with charge motion control (idle-emissions tumble flaps) and imrc (intake manifold runner control). But I'm no digital tuner.
Also, and I realize this is Duratec Tuning, but,
SVT Zetecs have been know to have "overactive" knock sensors... and with the gasoline octane rating discussions we've had here in Duratec Tuning it leads me to belive that some PZEV Duratecs may run better on a mid-grade gasoline (89) than 87...
I've never tried anything other than 87 in my 2003 2.3 Duratec PZEV ZX3 (with only a CAI, flex and 2.25" exhaust) because it runs so well. It's so smooth and incredibly torquey for a four banger.