Interpret my static air pressure numbers

[tedkidd]

The reason is that I like to do a night setback and drop the temp from 71 to 65 overnight. Most nights the temp only drops to 66-68 overnight, though on very cold nights it will go down to 65 by morning.

Why do you like to do that?

Right now the furnace runs about twice as often in low stage as in high, and I would prefer it to be locked in high to get maximum efficiency for that short period of time in the morning the furnace runs.

Why would you prefer that? What do you mean by maximum efficiency?

My manual J had my heat loss at design conditions to be 34,000. So it is true I could get by with only low stage, but why use the furnace at its least efficient?

Why would you think that's least efficient?

What is your static pressure at low, and high?
What is your duct leakage at low? At high?
What pressure imbalances occur in your rooms at low? At high?
How much pressure induced leakage is occurring at low fire? At high?
How much heat gets delivered to occupied space per therm burned on low? How much on high?
And at what temperature is comfort achieve with a low fan rate? How much warmer must the setting be for a rapidly cycling high blowing fan rate?
You aren't buying temperature, you are buying comfort. http://bit.ly/comfortcalculator

If you look at this just looking at one tiny slice, it's like your nose is pressed up against a work of art. Would you really do THAT and think you were seeing the whole picture?