discussion about aeroelastic analysis of IEA 15 MW WT

I have done the aeroelastic analysis of the IEA 15 MW wind turbine reference (mounted on the floating platform VolturnUS) enabling the first and second flapwise and edgewise mode of the blade in elastodyn. I’m not sure if the results make sense. I compared the results between it and a rigid body blade (the first and second flapwise and edgewise mode disabled). The figures show the power, blade pitch and pitch of the platform.
The results are significantly different when the first and second flapwise mode are enabled together. If I enable the first mode only, or the second mode only, or edgewise only, the results are very similar to the rigid body.
do you think there is something wrong with the analysis?
thank you very much for your help,
Best regards

I solved the problem by myself. The problem was that the delta time of the simulation was too high (dt=0.05), but if I set dt =0.01 the two curves are the same.