While using the CLOCC SS316 0.5ohm coil in Power Mode is safe & perfectly acceptable, I would prefer to use it in SS TC mode in the 450-480deg f range as my experience with TC is that coils just last longer in this mode.
If I were to vape in Power mode, I would use the CLOCC NiCr 1.5ohm coil as the accuracy of NiCr TC is questionable at best since it is debatable that TC on NiCr is even possible (If Evolv can't do it, I sincerely doubt Kanger can). If I was going to blow a coil's life by using in power mode, I would use the NiCr one, but that is just me.
Since the wattage range of the CLOCC SS316 0.5ohm coil is 15w-50w, you are certainly using it in proper range recommended range, (but I always found 30w to be a bit high for Kanger Coils in Subtanks under power mode during at temp use & usually stayed in 20w-25w range). My initial experience with Cupti is that it wasn't until my third tank that the true flavor of the coil began to come through though so your coil just may need a bit more time to begin to shine through.