I don't think the issue is heat/cold it is moisture change that causes truss uplift.

The coefficient of linear expansion of both softwoods and hardwoods is 0.0000017 to 0.0000025" per degree F. On a 30' truss that changes temperature 25 degrees the dimensional change of the 30' tension chord would only be 0.02". Not enough to explain the uplift.

Longitudinal dimensional change of soft wood is 0.1 to 0.2% and juvenile wood can shrink 2%. SYP is notorious for having juvenile wood. The same 30' truss that expands/contracts .2% moves nearly 3/4" and with ends restrained by attachment to the walls, could easily show uplift of up to 3"

In my world, forget heat/cold as a driver for wood movement and think MOISTURE CHANGE!

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Mike Drorbaugh