I see in the user's manual that harmonic forces/displacements have the formula F(t) = A * cos(wt + phi) or F(t) = A * cos(wt - phi).

Tested by results, the correct formula (used by software) is with minus sign.

F(t) = A * cos(wt - phi)

I don't know why this choice, and I don't want to discuss (If someone knows... please explain me)

But important... please , I think it can be considered by Intergraph to change pages 709 and 719 of the user's manual, where the formula is with plus sign referring to phase angle. It can lead the user to error in applying correct phasing.
All formulas with minus is better...