You should find that the calculation time of FreqShiftF is about 1ms longer than FreqShiftF2 when freqShift_Hz is not zero. The problem you were having with FreqShiftF2 is likely due to Osc_Vect_Q and Osc_Vect_I not being static.
Edit: also note that the translation part of FreqShiftF2 is missing the cross multiplication from the original code. Also, I removed freqAdjFactor. It's just an undocumented gain factor.
You should find that the calculation time of FreqShiftF is about 1ms longer than FreqShiftF2 when freqShift_Hz is not zero. The problem you were having with FreqShiftF2 is likely due to Osc_Vect_Q and Osc_Vect_I not being static.
Edit: also note that the translation part of FreqShiftF2 is missing the cross multiplication from the original code. Also, I removed freqAdjFactor. It's just an undocumented gain factor.