CORC is one of the candidates for high magnetic field and large currents. We are interested in applying CORC to HTS power transformers that require not only large currents but also very low AC losses. We measured and calculated the magnetization losses of short straight CORC samples made of striated YBCO CC. The effect of the striation is certain for reducing the magnetization loss, but the effect is not directly dependent on the number of the striations and the applied field amplitude. For considering the effect in an HTS coil design, we defined striation effect factors from the measured data, and the factor used to revise the coil loss. To compare the patterns of the loss distributions in RACC and CORC coil, we also calculated the magnetization losses of an RACC coil. The RACC consists of 4 YBCO CC with the width of 4mm and the RACC coil had 22 turns in two layers.