5GNR hOFDMDemodulate function

Hi, I knows that 5GNR (Rel-15 38.211 5.3.1) use CP-OFDM, same as LTE. I bought 5G toolbox (R2019a), I use hOFDMDemodulate function in Matlab. but, I confirm that this function is operated such as F-OFDM. fftstart point is changed by cpFraction and there is phase correction after extracting FFT part. I think that it is different from 3GPP release-15, actually.

please tell me that which OFDM is used for matlab 5G toolbox and why matlab is different from 3GPP Rel-15.

thank you in advance.