According to ACI 318-19
For fy exceeding 550 MPa, the calculated deflection limits in 8.3.2 shall be satisfied assuming a reduced modulus of rupture
fr =0.41(fc’)^0.5 .
Note that fr used in CSI Programs like (SAFE) equal 0.33(fc’)^0.5 this value is recommended by ACI 435R-95 when using FEA.